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Logical

Logical

https://www.xkcd.com/1901

https://www.explainxkcd.com/wiki/index.php/1901:_Logical

[White Hat is spreading his arms and facing Cueball.] White Hat: We wouldn't have all these problems if people just learned to be more logical and science-driven instead of relying on feelings . Cueball: Oh? What study are you basing that on? White Hat: It just seems obvious! White Hat: I mean, look at the crap these idiots believe!

White Hat says that problems in society could be avoided if people relied on logic and science rather than feelings—but when Cueball presses him to back up his claim, White Hat insists that his claim must be true, because it just seems obvious (to White Hat), and what the opposition (which he dismissively refers to as "these idiots") believes is crap in his opinion. Since White Hat refers to all people in general and since he falls in the same trap as he complains about, using his feelings for his case instead of logic and science, White Hat's argument is both fallacious and hypocritical. The title text is White Hat's opinion, where he states that he has always said that people just need more common sense . He then adds, but not the kind of common sense that lets them figure out that he is condescending (i.e. talking down to them) and basically thinks that they are stupid. If they did, they would probably realize that White Hat considers himself smarter than them, and likely feel insulted and take retribution. (At the same time, he may himself lack this form of "common sense," as Cueball's question could be seen as a veiled insult highlighting White Hat's hypocrisy.) When people talk about "common sense", they often really mean "they should think like I do". Using a term like "common sense" as a proxy for one's personal point of view implies that everyone else should have the same point of view. This discredits the fact that each person has their own point of view, completely valid to their own mind, and any attempts to push someone else's idea of a "common sense" upon them usually feels like "being talked down to" because of the implicit "fact" that that person's point of view is "common" and makes "sense", and therefore they must be smarter than you if you don't agree with their "common sense". Ironically, there is some inconclusive scientific evidence against White Hat's position. It is possible that effective rational thought depends on feelings and emotions as a preprocessing step. For example, people with damage to the ventromedial prefrontal cortex lose their ability to have gut reactions to decision options. In Antonio Damasio 's research, they were unable to make good decisions in everyday life. This may be because every option seems emotionally as good as any other and the brain is not good at conscious processing of large numbers of alternatives. See Descartes' Error by Damasio (1994) and The Righteous Mind by Haidt (2012). [White Hat is spreading his arms and facing Cueball.] White Hat: We wouldn't have all these problems if people just learned to be more logical and science-driven instead of relying on feelings . Cueball: Oh? What study are you basing that on? White Hat: It just seems obvious! White Hat: I mean, look at the crap these idiots believe!

State Borders

State Borders

https://www.xkcd.com/1902

https://www.explainxkcd.com/wiki/index.php/1902:_State_Borders

[An outline map of the United States is shown, including state boundaries. The following edit marks are shown in red text:] [Minnesota's Northwest Angle is circled] Give to Canada [Border between Wisconsin and Michigan's Upper Peninsula is crossed out] This should be Wisconsin [New York's Long Island is circled, with arrows and question marks pointing to New Jersey and Connecticut] Move Long Island to NJ or CT or make it its own state [New York's eastern border has been straightened] [Wyoming's western border is moved to align with that of Colorado. The Montana/Idaho and Idaho/Utah borders are extended to reach the new border. Similarly, Colorado's eastern border is moved to align with that of Wyoming, and the Nebraska/Kansas border has been extended] Align to grid [West Virginia's northern panhandle has been given to Ohio and part of its eastern panhandle has been given to Maryland. In return, Western Maryland has been given to West Virginia. The altogether effect is that West Virginia and Maryland have more compact shapes] Clean Up [Rhode Island has been enlarged to encompass southeastern Massachusetts, and Delaware now takes up the entire Delmarva Peninsula] Enlarge Rhode Island & Delaware [The Oklahoma Panhandle has been extended west until it reaches Nevada, taking the northernmost parts of Arizona and New Mexico with it] If we're going to have a panhandle, why not commit to it? [The Missouri Bootheel has been given to Arkansas] Fix this thing [The part of Virginia west of the Appalachian Mountains has been given to Kentucky] [The southwestern and eastern borders of Nevada have been extended into Arizona until they meet a point. A part of California is slightly extended to reach the revised border] [Parts of Arizona and New Mexico have been ceded to Mexico, and part of Texas has been given to New Mexico, so that the southern borders of Arizona and New Mexico and the northern border of the Trans-Pecos area of Texas collectively form a straight line] Clean Up [Parts of northeastern Texas have been given to Arkansas and Louisiana] [The northern and southern borders of Tennessee have been straightened] Straighten to fix survey errors [A line has been traced along the coasts of South Carolina, Georgia, and northern Florida] Good curve! Keep. [Alaska's southeastern panhandle has been circled] Let's be honest - this should be Canada, too. [The Alabama/Florida border has been erased, and Alabama's eastern border has been extended south until it meets the Gulf of Mexico] Why should Florida get Alabama's coastline? It has plenty. [Caption below the panel:] It was scary when graphic designers seized control of the country, but it turned out they just wanted to fix some things about the state borders that had always bothered them.

In this comic, graphic designers take control of the United States, but the only thing they do is to change the state and national borders, using primarily aesthetic criteria. State and national borders have generally emerged from some combination of political decisions, natural boundaries, control of natural resources, and, to some degree, from chance. As the comic implies, some borders originally resulted from surveying errors, but became encoded by law and tradition, and thus were never changed. Despite the caption's rather blasé reaction to the graphic designers' master plan, the changes they propose could be rather tumultuous. Political boundaries are difficult to change because rewriting them places entire populations in different states or even different countries. Even within the US, changing a population from one state to another has serious implications. A different state means different laws, tax obligations, public benefits, business regulations, infrastructure support, etc. It would also mean that control of some very substantial natural resources would be transferred from one state to another. More significantly, the suggestion to cede portions of the US to Canada and Mexico would be a much bigger deal, forcing residents of those areas to either leave their homes, businesses, and communities or surrender their current nationality and apply for citizenship in another country. The joke behind the comic is that graphic designers would tend to ignore these practical concerns and pay more attention to a map looking orderly. This comic hints at the fact that it is indeed Randall who wants to see these changes made. In the title text, the graphic designers have a civil war between the ones that favor "panhandles" in the borders, such as the Oklahoma one which is enlarged in the map, the Florida one which is removed in the map, and maybe others such as the Texas region known as the "Texas panhandle". However, as graphic designers, they get too caught up in making the flag designs for their faction to actually fight. Randall has shown interest for vexillology (the study of flags) in the past. [An outline map of the United States is shown, including state boundaries. The following edit marks are shown in red text:] [Minnesota's Northwest Angle is circled] Give to Canada [Border between Wisconsin and Michigan's Upper Peninsula is crossed out] This should be Wisconsin [New York's Long Island is circled, with arrows and question marks pointing to New Jersey and Connecticut] Move Long Island to NJ or CT or make it its own state [New York's eastern border has been straightened] [Wyoming's western border is moved to align with that of Colorado. The Montana/Idaho and Idaho/Utah borders are extended to reach the new border. Similarly, Colorado's eastern border is moved to align with that of Wyoming, and the Nebraska/Kansas border has been extended] Align to grid [West Virginia's northern panhandle has been given to Ohio and part of its eastern panhandle has been given to Maryland. In return, Western Maryland has been given to West Virginia. The altogether effect is that West Virginia and Maryland have more compact shapes] Clean Up [Rhode Island has been enlarged to encompass southeastern Massachusetts, and Delaware now takes up the entire Delmarva Peninsula] Enlarge Rhode Island & Delaware [The Oklahoma Panhandle has been extended west until it reaches Nevada, taking the northernmost parts of Arizona and New Mexico with it] If we're going to have a panhandle, why not commit to it? [The Missouri Bootheel has been given to Arkansas] Fix this thing [The part of Virginia west of the Appalachian Mountains has been given to Kentucky] [The southwestern and eastern borders of Nevada have been extended into Arizona until they meet a point. A part of California is slightly extended to reach the revised border] [Parts of Arizona and New Mexico have been ceded to Mexico, and part of Texas has been given to New Mexico, so that the southern borders of Arizona and New Mexico and the northern border of the Trans-Pecos area of Texas collectively form a straight line] Clean Up [Parts of northeastern Texas have been given to Arkansas and Louisiana] [The northern and southern borders of Tennessee have been straightened] Straighten to fix survey errors [A line has been traced along the coasts of South Carolina, Georgia, and northern Florida] Good curve! Keep. [Alaska's southeastern panhandle has been circled] Let's be honest - this should be Canada, too. [The Alabama/Florida border has been erased, and Alabama's eastern border has been extended south until it meets the Gulf of Mexico] Why should Florida get Alabama's coastline? It has plenty. [Caption below the panel:] It was scary when graphic designers seized control of the country, but it turned out they just wanted to fix some things about the state borders that had always bothered them.

Bun Trend

Bun Trend

https://www.xkcd.com/1903

https://www.explainxkcd.com/wiki/index.php/1903:_Bun_Trend

[Beret Guy holds a stick and points at a board next to him. The board contains a picture of a rabbit, a data point graph, and other notes.] Beret Guy: Good morning, Governor. Our tracking systems show a rapid increase in the number of buns around the Capitol. [Hairy is sitting at an office desk and facing Beret Guy in a frameless panel.] Hairy: Buns? Beret Guy: Yes; there's been a long-term upward trend, but it has accelerated recently. Hairy: The trend in... rabbits. Beret Guy: Yes. [Beret Guy takes out his phone.] Hairy: So... so what? Beret Guy: So if you want to see some buns, there are lots of them outside! [Beret Guy's phone vibrates] Phone: beep! Beret Guy: Ooh! Beret Guy: There's a small one right now! [Zoom-in on Beret Guy.] Hairy (offscreen): Do you... actually work for me? Beret Guy: Almost certainly. We had an election, right? I wrote my name in on the thing. Hairy (offscreen): Security? Beret Guy: It's been an honor to serve.

In this comic, Beret Guy takes his bun shenanigans to the state government, reporting to the governor that the number of buns around the capitol has shown a rapid increase. The governor is confused, then finally comes to grasp that Beret Guy is talking about rabbits , lots of which can be seen if he would just go outside (by the way, there is a small one RIGHT NOW !). Elections in the United States often have a blank spot on the ballot for the voter to write the name of a write-in candidate . Beret Guy thinks he works for the governor because he wrote his name in on the ballot. This does not mean that he actually works for the governor. [ citation needed ] The governor finally takes appropriate action by calling security, and Beret Guy confronts his fate with poise and honor. Indeed, the readiness with which he accepts his removal almost seems to suggest that he doesn't belong, which would be an unusual level of awareness for his character. Alternatively, Beret Guy might have misinterpreted the governor's request for security as a question of whether he works in security, or simply ignorance. This also may be an ironic reference to the rapid turnover in President Trump 's staff. "Buns" have been mentioned previously in 1682: Bun and 1871: Bun Alert . Beret Guy's uncertain position in the government is very similar to the way he treats and operates his business. In the title text, experts characterize the ecological impact of a large number of bunnies as "adorable" instead of giving information on how the rabbits are affecting the environment. [Beret Guy holds a stick and points at a board next to him. The board contains a picture of a rabbit, a data point graph, and other notes.] Beret Guy: Good morning, Governor. Our tracking systems show a rapid increase in the number of buns around the Capitol. [Hairy is sitting at an office desk and facing Beret Guy in a frameless panel.] Hairy: Buns? Beret Guy: Yes; there's been a long-term upward trend, but it has accelerated recently. Hairy: The trend in... rabbits. Beret Guy: Yes. [Beret Guy takes out his phone.] Hairy: So... so what? Beret Guy: So if you want to see some buns, there are lots of them outside! [Beret Guy's phone vibrates] Phone: beep! Beret Guy: Ooh! Beret Guy: There's a small one right now! [Zoom-in on Beret Guy.] Hairy (offscreen): Do you... actually work for me? Beret Guy: Almost certainly. We had an election, right? I wrote my name in on the thing. Hairy (offscreen): Security? Beret Guy: It's been an honor to serve.

Research Risks

Research Risks

https://www.xkcd.com/1904

https://www.explainxkcd.com/wiki/index.php/1904:_Research_Risks

[A chart with two crossing lines with double arrows. Each arrow is labeled:] Y axis top: High Y axis bottom: Low X axis left: Low X axis right: High [Near each of the "high" ends of the two axis there is a label written in gray, with a line pointing to the relevant axis:] Y axis: Risk of your research being used by a supervillain for world domination X axis: Risk of the thing you're studying breaking free from your facility and threatening the local population [The following points are on the charts upper left quadrant (in reading order):] Prosthetics Neuroscience Laser Optics Pharmacology Materials Science Sociology History Psychology [The following points are on the charts upper right quadrant (in reading order):] Robotics Genetic Engineering Chemistry Microbiology [The following points are on the charts lower left quadrant (in reading order):] Geology Linguistics Paleontology Astronomy Molasses Storage Dentistry [The following points are on the charts lower right quadrant (in reading order):] Botany Entomology Mycology Marine Biology Ornithology

This is a comparison of the possibility of the subjects of various sciences being a threat to humanity. It can either be an autonomous threat to the local population (i.e. by escape from a lab), or as part of a supervillain's scheme to rule the world . In general, areas of study that could be used by supervillains, but are unlikely to "break free" refer to technologies that are unlikely to be self-propagating or self-maintaining, but could be used as weapons or for some other form of control. Subjects that could break free, but are unlikely to be used by supervillains are all living organisms (which could presumably breed and multiply without human intervention), but which have little potential as weapons. Areas of study that fall in both categories are either more controllable forms of biology (microbiology, genetic engineering), forms of technology that could become self-propagating (robotics), or a study where a release could be dangerous without being self-propagating (chemistry). The category of a low risk of either could, of course, contain many fields of study, as most research fields have limited potential for weaponry and little danger of going out of control on a large scale. See the chart below for detailed explanations of each scatter point. There have so far been several similar comics with such scatter plots . See for instance 1242: Scary Names , 1468: Worrying , 1501: Mysteries and 1701: Speed and Danger . The title text is related to the Molasses Storage entry at the bottom left of the chart, and references the Great Molasses Flood , also known as the Great Boston Molasses Flood. It occurred on January 15, 1919 in the North End neighborhood of Boston , Massachusetts (the state in which Randall lives). A large molasses storage tank burst and a wave of molasses rushed through the streets at an estimated 35 mph (56 km/h), killing 21 and injuring 150. The joke in the title text is that in 2031 (14 years after the release of this comic) the Canadian Space Agency has an even more serious disaster, which will be known as the orbital maple syrup delivery disaster. The title text claims that this disaster then became the deadliest confectionery containment accident, thus killing more than 21 people. Note : percentages refer to the position of the center of the smallest enclosing rectangle around each name. 0% and 100% correspond to the low and high arrow tips, respectively. [A chart with two crossing lines with double arrows. Each arrow is labeled:] Y axis top: High Y axis bottom: Low X axis left: Low X axis right: High [Near each of the "high" ends of the two axis there is a label written in gray, with a line pointing to the relevant axis:] Y axis: Risk of your research being used by a supervillain for world domination X axis: Risk of the thing you're studying breaking free from your facility and threatening the local population [The following points are on the charts upper left quadrant (in reading order):] Prosthetics Neuroscience Laser Optics Pharmacology Materials Science Sociology History Psychology [The following points are on the charts upper right quadrant (in reading order):] Robotics Genetic Engineering Chemistry Microbiology [The following points are on the charts lower left quadrant (in reading order):] Geology Linguistics Paleontology Astronomy Molasses Storage Dentistry [The following points are on the charts lower right quadrant (in reading order):] Botany Entomology Mycology Marine Biology Ornithology

Cast Iron Pan

Cast Iron Pan

https://www.xkcd.com/1905

https://www.explainxkcd.com/wiki/index.php/1905:_Cast_Iron_Pan

[White Hat is holding a pan by the handle pointing to the frying surface as he shows it to Cueball.] White Hat: Never clean a cast-iron pan with soap. It destroys the seasoning. Cueball: Got it. [White Hat shift the pan to his right hand and lowers it to his side holding a finger up in front of Cueball.] White Hat: If you ever let soap touch the pan, throw it away. You're clearly not up to taking care of it. Cueball: Wow, okay. [In a frame-less panel White Hat has taken the pan back to the first hand holding on the the edge while he holds his other hand close to the frying surface.] White Hat: Apply moisturizer to the pan daily to keep it fresh. Cueball: ...Moisturizer? White Hat: Do you want it to get all wrinkly? Cueball: ...I...guess not. [White Hat has shifted the pan to the second hand again holding it by the handle away from Cueball, while pointing at Cueball with the other hand.] White Hat: Twice a year, fill the pan with iron filings and leave it in direct sunlight for 24 hours. Cueball: Wait. 24 hours of sun? White Hat: If you're not willing to travel to the Arctic, you don't deserve cast iron.

White Hat is discussing tips for maintaining Cast-iron cookware . Cast-iron cookware is well-loved and often promoted by cooking aficionados, but requires more effort and care to maintain than many other modern forms of cookware. This strip satirizes both the amount of effort involved, and the attitude of connoisseurs who look down on people who are unwilling to put in such effort. In typical xkcd fashion, the comic starts off somewhat realistic and escalates to absurdity. White Hat tells the old myth (debunking articles: Lifehacker , The Kitchn , Serious Eats ), that "you shouldn't wash your cast iron pan with soap since it destroys the seasoning ", to Cueball . Seasoning is the process of treating the surface of a pan with a stick-resistant coating formed from polymerized fat and oil on the surface. Although it may not be a problem to use soap on your seasoned cast iron pan, you should still proceed with care with how you treat it. White Hat starts to exaggerate; he tells him that if he ever as much as let soap touch the pan he should just throw it away, as that fact alone would prove that he would not be up to taking care of such a precious possession. This is a kind of scare tactic that might make Cueball believe this and anything else he tells him. White Hat continues to give dubious advice to the point of absurdity, and Cueball becomes more and more wary of it. His next word of advice is to apply moisturizer to the pan daily to keep it fresh. Cueball asks why and is told that it is to avoid the pan getting wrinkles . This implies that the pan would age like a human and get wrinkles. This is, of course, nonsense [ citation needed ] , but Cueball is not yet ready to dismiss White Hat's advice. The final piece of advice is that twice a year Cueball should fill the pan with iron filings and leave it in direct sunlight for 24 hours. Both details are intended to be absurd. For one, neither the iron filings nor the sunlight appear to serve any actual purpose . Second, 24 continuous hours of direct sunlight is impossible to achieve in most places. North of the Arctic Circle (often shortened to simply "the Arctic ") there will be at least one day a year where the sun does not set. While one might assume that a combined total of 24 hours over couple of days would be sufficient, White Hat implies that it's necessary to travel to very remote locations in very specific parts of the year to meet an extreme requirement. He further casts an unwillingness to meet this unreasonable standard as rendering a person unworthy of cast iron. White Hat's strict tone "If you're not willing to travel to the Arctic, you don't deserve cast iron" might also suggest that cast iron is a special almost-legendary metal similar to Damascus steel or its fictional counterpart Valyrian steel and requires distant travel to obtain/maintain. This is likely a parody of the level of reverence cast iron cookware tends to receive in certain circles. Despite there being alternatives that are much easier to maintain, a significant number of cooks insist that cast iron has qualities that make it worth the amount of effort involved. In the title text, White Hat mentions that, if you wish to evenly space the two 24 hours of sun each year, it is easiest to alternate between the Arctic and the Antarctic regions. But this will mean that you have to travel a long distance at least once a year; even if you already lived inside one of the Polar Circles , you would have to travel to the other at least once a year. It is implied that you do not have to space them evenly. As he mentions, some people just go to the Arctic twice a year near the equinoxes . However, according to White Hat, this is not the same, probably because it doesn't lead to an exact six-month spacing and the sun would stay very low on the horizon and the sunlight would not be as intense. In order to accomplish this other scheme, it also means that they would actually have to go very close to the North Pole (or South Pole ), as this is the only place with midnight sun around the equinoxes. So, in principle, this would be much more cumbersome than just going inside the southernmost part of the Arctic region at the summer solstice , and similarly the northernmost part of the Antarctic region at the northern hemisphere's winter solstice (which will be the summer solstice in the southern hemisphere). When looking at it like this, it may seem that White Hat actually means that you should always go to the poles, rather than just to a place with 24 hours of sunlight, in order to have the sun high in the sky as well. [White Hat is holding a pan by the handle pointing to the frying surface as he shows it to Cueball.] White Hat: Never clean a cast-iron pan with soap. It destroys the seasoning. Cueball: Got it. [White Hat shift the pan to his right hand and lowers it to his side holding a finger up in front of Cueball.] White Hat: If you ever let soap touch the pan, throw it away. You're clearly not up to taking care of it. Cueball: Wow, okay. [In a frame-less panel White Hat has taken the pan back to the first hand holding on the the edge while he holds his other hand close to the frying surface.] White Hat: Apply moisturizer to the pan daily to keep it fresh. Cueball: ...Moisturizer? White Hat: Do you want it to get all wrinkly? Cueball: ...I...guess not. [White Hat has shifted the pan to the second hand again holding it by the handle away from Cueball, while pointing at Cueball with the other hand.] White Hat: Twice a year, fill the pan with iron filings and leave it in direct sunlight for 24 hours. Cueball: Wait. 24 hours of sun? White Hat: If you're not willing to travel to the Arctic, you don't deserve cast iron.

Making Progress

Making Progress

https://www.xkcd.com/1906

https://www.explainxkcd.com/wiki/index.php/1906:_Making_Progress

[Megan is sitting and looking at a laptop.] Megan: I started the day with lots of problems. Megan: But now, after hours and hours of work, Megan: I have lots of problems in a spreadsheet .

Megan has procrastinated made progress on a large backlog of problems. While she started the day with lots of problems, she has entered those problems into a spreadsheet. While this could potentially allow her to tackle her problems in a more organized way and fix them more quickly, the humor lies in that none of the problems have actually been solved. Additionally, it's questionable whether this was worth the hours of effort she put into making the spreadsheet, and even whether the spreadsheet has made her problems any easier to tackle in the first place. The comic questions the usage of spreadsheets for anything beyond organization. In the title text she reveals that even her spreadsheet has a problem, because "#REF Circular Dependency detected" is a spreadsheet error meaning that a formula is (possibly indirectly) using its own cell in the equation. This is probably because she has used the Count() function to find the number of problems to be solved, but since one of those problems is not knowing how many problems she has, it is trying to include itself in the count. This counting problem may also be a metaphor for circular dependencies within the problems themselves, such that a solution to one problem would help solve another problem, but solving the first problem depends on a solution to the second problem (e.g. organizing a cluttered mess of objects requires room to work, which is not available because of all the clutter). Arguably, this has introduced a further problem, so she actually now has (#REF Circular Dependency detected)+1 problems. It's also possible, since Megan has chosen to interpret the error message as a numeric value representing the number of problems she has, that she is simply not good at using her spreadsheet software, which may be another problem that needs adding to her list. The use of COUNT() has, rather than returning an exact amount of problems to solve, implied that her original problems cause so many more that she does indeed have "countless problems". The error shown is similar to two different errors in the popular spreadsheet program Microsoft Excel : #REF! , which means that an invalid reference has been made (such as to a cell or sheet that has since been deleted), and circular references , which means that a certain cell's content has been made to depend, at some stage, on its own content, recursively . The latter could be because it directly refers to itself, or because it refers to another cell which, in some way, refers back to it. Most versions of Excel do not show circular references in the cell, next to where a #REF! error would be; rather they show an error message box and arrows drawn over the sheet which connect the dependencies of the cells involved in the error. However, since the comic does not specify which spreadsheet software Megan is using, Randall can simply make the errors up, to make the joke more quickly understandable, while clearly referencing errors that show in actual spreadsheet software. [Megan is sitting and looking at a laptop.] Megan: I started the day with lots of problems. Megan: But now, after hours and hours of work, Megan: I have lots of problems in a spreadsheet .

Immune System

Immune System

https://www.xkcd.com/1907

https://www.explainxkcd.com/wiki/index.php/1907:_Immune_System

[Ponytail is standing in front of a boardroom meeting, pointing to a presentation on a screen. Cueball, Megan and Hairbun are in the audience, sitting at a long table; an extra, unoccupied chair is in the front.] Ponytail: My body hosts an autonomous microscopic defensive swarm that will do anything to protect me. Ponytail: I have no ability to restrain it and I don't know my own power. Ponytail: So listen up. Ponytail: Sales grew by 4% this quarter... [Caption below the panel:] Business protip: You can strengthen any presentation by opening with a reminder about how cool immune systems are.

In this comic, Ponytail is delivering an informative report to a group of listeners, likely important managers of some large company. She begins her lecture by stating she is the host of a microscopic autonomous swarm that will do anything to protect her. She is referring to the immune system, which could technically be defined as a "microscopic autonomous swarm" that will do anything to protect her -- i.e destroy pathogens such as viruses and bacteria, both of which cause multitudinous diseases in humans. Like many of the systems of the body, the immune system cannot be controlled by conscious thought, and should not be taken as unordinary. The caption below reveals the method behind her madness. Randall claims that beginning any business presentation with a surreal description of one's own immune system is guaranteed to strengthen your case. Whether or not this is actually the case is irrelevant, the point of the comic is about "how cool the immune system is", and explains its coolness through an unconventional description of how the process works. Additionally, Ponytail's description implies more potential power over external entities than an immune system typically has, perhaps to to gain more respect/fear from the speaker's audience. The title text elaborates further on this, stating that similar arguments can be used in negotiation. The description of the immune system is deliberately misleading, implying that the immune system may attack the other negotiator if the terms of the deal aren't satisfactory. While it is correct that your immune cells cannot be reasoned with [ citation needed ] and theoretically it could cause an anaphylactic shock in the targeted organism, the veiled threat omits the fact that the immune system 1) is unaffected by external negotiations conducted by its host, 2) is incapable of attacking things outside of the body, and 3) would have to overcome the target's own immune system. [Ponytail is standing in front of a boardroom meeting, pointing to a presentation on a screen. Cueball, Megan and Hairbun are in the audience, sitting at a long table; an extra, unoccupied chair is in the front.] Ponytail: My body hosts an autonomous microscopic defensive swarm that will do anything to protect me. Ponytail: I have no ability to restrain it and I don't know my own power. Ponytail: So listen up. Ponytail: Sales grew by 4% this quarter... [Caption below the panel:] Business protip: You can strengthen any presentation by opening with a reminder about how cool immune systems are.

Credit Card Rewards

Credit Card Rewards

https://www.xkcd.com/1908

https://www.explainxkcd.com/wiki/index.php/1908:_Credit_Card_Rewards

[Cueball sits at a desk and is on his laptop. Hairy stands behind him.] Cueball: I'm trying to figure out which of these credit card rewards programs is best given my spending. [Cueball leans backwards in a frameless panel.] Cueball: But at some point, the cost of the time it takes me to understand the options outweighs their difference in value. [Close-up of Cueball's head and torso.] Cueball: So I need to figure out where that point is, and stop before I reach it. Cueball: But... when I factor in the time to calculate THAT , it changes the overall answer. [Cueball has his arms outstretched.] Hairy: I question the assumption that you'd otherwise be spending your time on something more valuable. Cueball: Come on, I could be failing to optimize so many better things!

A credit card , at its most basic form, is a loan contract to an individual from a bank . Like all contracts, the bank will offer several different types in an attempt to appeal to a large number of individuals. Unlike traditional loans which focus on a single item (car, house, boat, etc), a credit card is an unsecured loan geared towards daily and weekly transactions. Because these transactions cover a wide variety of items, credit cards can be further tweaked towards offering benefits in certain areas. For example, gas purchases, or even gas purchases through a single retail chain, can offer higher rewards on one type of plan vs. other plans. These benefits, typically called rewards, have several different options. " Cashback " is a reward where the individual is given money back when they make a purchase that follows certain rules spelled out in the contract. "No interest " is a reward where the individual is not charged interest on their purchases if they pay the loaned money back within a specified amount of time. "Points" are similar to the cashback program, but are typically reserved towards purchasing a single large item or plan. Points towards a vacation is a popular option. Besides these three types of rewards, the number of actual rewards to pick from are limited only by the creativity and fiscal limitations of the issuing bank. Cueball is trying to choose the optimal credit card program that will result in the biggest savings for his typical income and spending patterns. He will need to trade off the value of any benefits against the cost of any fees and interest charges that would be incurred. This could become quite complex if he is prepared to consider taking out multiple cards to access the various benefits they offer, and in order to get the best outcome he may need to regularly shift funds from one card to another to make use of introductory or short-term offers. On top of all this, the incentives on offer may change his spending behaviour, which would further impact the calculation. (This table was actually created in 1205: Is It Worth the Time? ) He then realizes that there is a cost of him spending time on optimizing his choice, so he wants to limit the time spent doing the optimizing so that it doesn't outweigh the maximum advantage he might gain from choosing the best deal. Finding a definite answer to the time at which he should stop his optimization efforts is hard, if not impossible, because the fact that he cannot complete them means that he probably cannot know for certain what the maximum advantage would be; he will have to rely on a probabilistic solution instead. To further complicate things, he will need to factor in the cost of the time spent solving the problem of how long to spend on optimizing (and, presumably, the time spent solving that problem, and so on infinitely). Hairy challenges a hidden assumption that Cueball's time has significant value, which would imply that if he wasn't worrying about this problem. he would be doing something more productive, implying that Cueball's obsession with optimization is lame enough to suggest that he does not actually have any more worthwhile interests to pursue. His response that he "could be failing to optimize so many better things!" just further proves Hairy's point, and suggests that Cueball is aware of both the big flaw in his reasoning and the fact that, when he attempts to optimize things, it seldom really helps his situation. The title text further expands the idea. Cueball wants to work out which optimization problems he could most productively work on first. However, his proposed idea of creating a spreadsheet to calculate this may well end up costing more in time than the benefit he would gain from working on them in priority order (particularly since, on this evidence, the potential gains from each problem are marginal at best). Furthermore, if the 'several variables' he needs to consider lead to the kind of complexity seen in the credit card problem, a spreadsheet may not be the best tool for the kind of calculations he needs to perform. The idea of spending more time organising tasks in a spreadsheet than you actually do working on the tasks was previously featured in 1906: Making Progress . [Cueball sits at a desk and is on his laptop. Hairy stands behind him.] Cueball: I'm trying to figure out which of these credit card rewards programs is best given my spending. [Cueball leans backwards in a frameless panel.] Cueball: But at some point, the cost of the time it takes me to understand the options outweighs their difference in value. [Close-up of Cueball's head and torso.] Cueball: So I need to figure out where that point is, and stop before I reach it. Cueball: But... when I factor in the time to calculate THAT , it changes the overall answer. [Cueball has his arms outstretched.] Hairy: I question the assumption that you'd otherwise be spending your time on something more valuable. Cueball: Come on, I could be failing to optimize so many better things!

Digital Resource Lifespan

Digital Resource Lifespan

https://www.xkcd.com/1909

https://www.explainxkcd.com/wiki/index.php/1909:_Digital_Resource_Lifespan

My access to resources on [SUBJECT] over time: [Below, a timeline and a graph with gray bars is shown:] [1980s-past 2020:] Book on subject [Early 2000s-past 2020:] [SUBJECT].pdf [2000-2010:] [SUBJECT] web database Site goes down, backend data not on archive.org [Small bar, 2000-2016/17:] Java frontend no longer runs [2010-2015/16:] [SUBJECT] mobile app (Local university project) Broken on new OS, not updated [2000-2010:] [SUBJECT] analysis software Broken on new OS, not updated [Late 1990s-late 2000s:] Interactive [SUBJECT] CD-ROM CD scratched; new computer has no CD drive anyway. [1980s-past 2020:] Library microfilm [SUBJECT] collection [Caption below the panel:] It's unsettling to realize how quickly digital resources can disappear without ongoing work to maintain them.

In this chart, Randall laments the tendency of digital resources to quickly become obsolete or non-functional. By taking a general subject, such as xkcd's core subjects of "romance, sarcasm, math, and language", one can see that a useful tool such as a smartphone or computer app or interactive CD-ROM (essentially, software) does not have the lasting power of printed books (e.g. textbooks, for many general subjects) and microfilm/microfiche. The printed resources, not having to rely on a computerized platform for use, are far more reliable despite being less mobile and taking up physical space. The only digital source which is still working is Portable Document Format (aka PDF) which encapsulates fixed layout flat documents, and is supported for years already by Adobe Systems and is part of ISO standards, so has a widespread support, and should be still viewable in foreseeable future. The title text makes a statement that libraries do not require the support of original authors/experts to organize and store vast resources for any subject imaginable. This is true, but omits the fact that ongoing efforts are required by experts in information organization and storage -- namely, librarians. Physical books and microfilm/microfiche need controlled storage environments, manual handling for storage, retrieval, distribution (in library terms, "circulation"), and the like. Thus, a library can require significant resources in personnel and facilities, but is usually seen as a "public good" for the benefit of society; thus, many communities and educational institutions invest in creating and maintaining a library despite the costs. Archive.org refers to The Internet Archive , a non-profit organization that maintains the Wayback Machine , one of the largest archives of the World Wide Web . When a website is taken offline, copies of its content can often be found backed-up on the Wayback Machine. The Wayback Machine is primarily designed to back up websites , however, and will often not be able to save information stored in a site's databases , as alluded to in the comic. The Internet Archive has a part for non-website archives, but it cannot hold recent databases either due to copyright problems. My access to resources on [SUBJECT] over time: [Below, a timeline and a graph with gray bars is shown:] [1980s-past 2020:] Book on subject [Early 2000s-past 2020:] [SUBJECT].pdf [2000-2010:] [SUBJECT] web database Site goes down, backend data not on archive.org [Small bar, 2000-2016/17:] Java frontend no longer runs [2010-2015/16:] [SUBJECT] mobile app (Local university project) Broken on new OS, not updated [2000-2010:] [SUBJECT] analysis software Broken on new OS, not updated [Late 1990s-late 2000s:] Interactive [SUBJECT] CD-ROM CD scratched; new computer has no CD drive anyway. [1980s-past 2020:] Library microfilm [SUBJECT] collection [Caption below the panel:] It's unsettling to realize how quickly digital resources can disappear without ongoing work to maintain them.

Sky Spotters

Sky Spotters

https://www.xkcd.com/1910

https://www.explainxkcd.com/wiki/index.php/1910:_Sky_Spotters

[White Hat and Hairy are standing in front of some buildings. White Hat points to the sky while holding his smartphone in the other hand, while Hairy holds his smartphone up in both hands as he looks at the screen.] White Hat: That's odd—another PA-24 Comanche with red trim. Registered to a holding company, no recent flight plans. Hairy: I'll ask the forums if anyone knows who operates those. [Hairbun and an old man with a white sailor cap are standing in a field with rolling hills behind them. Hairbun is looking at the sky through her binoculars, which she has on a string around her neck. The man also looks up but he is holding his string attached binoculars down in front of him.] Hairbun: Goodness, I think that's a broad-winged hawk! Man with sailor cap: In November?! They should be long gone by now! Hairbun: I'll email the list. [Five people sit around a table in a boardroom, which presumably belongs to the government as the table has a circular insignia with an eagle in the center and unreadable text in the ring around the eagle and beneath the insignia. A man with slick black hair is sitting at the end of the table in an office chair. The other four are sitting behind the long side of the table; from the left they are Cueball, Megan, another version of Hairy with spikier hair, and to the right, Ponytail.] Man at the end of the table: Dammit, why are there so many different subcultures obsessed with staring at the sky? Ponytail: What else could we disguise our surveillance drones as? Cueball: Weather balloons? Ponytail: No, that gets the UFO people and the weather people. Ponytail: Don't know who's worse.

This comic explores how people with various hobbies notice strange things in the sky. In the first panel the plane enthusiasts White Hat and Hairy notice that there is a Piper PA-24 Comanche in the sky (apparently the most recent of several), belonging to a holding company that has filed no flight plans. Flight plans do not need to be filed for many short flights at lower altitudes in good weather, so for a small aircraft like the PA-24, the missing flight plan alone should not be unusual. Many government or company planes used for secret purposes, like FBI planes registered to fake companies , go a step further and are blacklisted from major databases. Regardless, it makes White Hat and Hairy wonder why, enough that they decide to post about it on their plane spotter forums. (See 1669: Planespotting ). The reference to red trim on the Piper PA-24 Comanche could be a reference to the livery of Janet Airlines which operates clandestine flights between Las Vegas , Area 51 , and other desert military bases , although these planes are in fact registered to the Department of the Air Force , rather than a holding company. In the second panel Hairbun and a male bird enthusiast are wondering why there is a broad-winged hawk in the area in November when many broad-winged hawks should have migrated south to areas like Florida and Central America. They decide to send a message to their birdwatching e-mail list. (See 1824: Identification Chart and 1826: Birdwatching ). The two birdwatchers in this panel look like the old version of Cueball and Megan in 572: Together . In the last panel, a committee from what appears to be the National Security Agency wonders how to disguise their drones so that people will not pay attention to them. The boss at the end of the table is lamenting the fact that both their bird- and plane-disguised drones have been noticed because of all these people constantly checking out the sky, also indicating that there are even more subcultures who are obsessed with things in the sky than the two mentioned already. Ponytail asks what else they could disguise their (secret) surveillance drones as, and Cueball suggests a weather balloon . But Ponytail shoots this down, since such a disguise would attract both the UFO enthusiasts and the "weather people" (presumably some regulation board that checks unauthorized use of meteorological survey balloons, or otherwise hobbyist meteorologists or perhaps even members of the Cloud Appreciation Society ). She then jokes that she doesn't know which is worse. Since most people consider UFO enthusiasts to be into conspiracies, the "weather people" may be annoyed by this. Maybe Randall is indicating that people trying to predict the weather are correct as often as those claiming to have seen a UFO... There are numerous instances of weather balloons being labeled as UFOs by enthusiasts, one of the most notable being the Roswell UFO incident , which for years was explained by the US military as a weather balloon crash, but turned out to be a nuclear test surveillance balloon. It is now known as the most thoroughly debunked UFO claim . In the title text, it is suggested that "lost birthday party balloons" should not attract too much attention. But then it is noted that it might make marine wildlife people angry, their concern probably being that balloons ultimately end up in some water body, which causes marine wildlife to get trapped in plastic and other synthetic material that was dumped in the water. (see Marine debris ) "Marine wildlife people with sharks" may be a reference to 585: Outreach , which also features a balloon carrying a shark. Another possible issue with disguising drones as "lost balloons" is that such balloons are quite rarely seen, and a sudden increase in the number of "lost balloons" seen would certainly raise suspicion even without a "spotting community" that focuses on them. Among other types of people looking at the sky, the comic doesn't even get around to mentioning the subject of comic 1644: Stargazing . [White Hat and Hairy are standing in front of some buildings. White Hat points to the sky while holding his smartphone in the other hand, while Hairy holds his smartphone up in both hands as he looks at the screen.] White Hat: That's odd—another PA-24 Comanche with red trim. Registered to a holding company, no recent flight plans. Hairy: I'll ask the forums if anyone knows who operates those. [Hairbun and an old man with a white sailor cap are standing in a field with rolling hills behind them. Hairbun is looking at the sky through her binoculars, which she has on a string around her neck. The man also looks up but he is holding his string attached binoculars down in front of him.] Hairbun: Goodness, I think that's a broad-winged hawk! Man with sailor cap: In November?! They should be long gone by now! Hairbun: I'll email the list. [Five people sit around a table in a boardroom, which presumably belongs to the government as the table has a circular insignia with an eagle in the center and unreadable text in the ring around the eagle and beneath the insignia. A man with slick black hair is sitting at the end of the table in an office chair. The other four are sitting behind the long side of the table; from the left they are Cueball, Megan, another version of Hairy with spikier hair, and to the right, Ponytail.] Man at the end of the table: Dammit, why are there so many different subcultures obsessed with staring at the sky? Ponytail: What else could we disguise our surveillance drones as? Cueball: Weather balloons? Ponytail: No, that gets the UFO people and the weather people. Ponytail: Don't know who's worse.

Defensive Profile

Defensive Profile

https://www.xkcd.com/1911

https://www.explainxkcd.com/wiki/index.php/1911:_Defensive_Profile

[A profile on an unknown social media site is displayed. The profile picture is a close-up image of Megan. The profile reads:] I speak my mind and don’t care who I offend. No filter. [In the next panel, the text is highlighted, and a context menu has appeared. There is a mouse pointer on the option "View translation".] Copy Select all View translation [selected] Print [In the last panel, the profile text is updated:] I don’t understand why people keep getting mad at me and I’m using this pep talk to convince myself that’s okay.

This comic demonstrates a theoretical feature which provides more honest interpretations of social media profiles. We see a profile for a person who says they have “no filters” and has no qualms about offending or upsetting anybody with their seemingly radical views. But the “translation” of the description reveals that it is a vastly insecure person who seems to have the problem of saying the wrong thing every time and so their profile description is a way for them to justify their comments. The title text continues, with the aggressive “NO DRAMA ZONE” turning out to mean that the user is merely trying to keep any offended or genuinely upset comments away from their page because they simply have no idea how to emotionally handle hurting someone’s feelings. Randall previously demonstrated another theoretical feature to address passive-aggressive behavior in 1085: ContextBot . And show Cueball having the same feeling in 1984: Misinterpretation . The comic’s feature may be based on the context menu option of the Google Chrome web browser to have a foreign language webpage translated to the user’s selected native language. However, in Google Chrome, the user may only translate the entire page, while in this comic the user may also select some text and have only the selected part translated. Also, Google Chrome uses Google Translate for translation by default, which cannot read minds like in the comic yet (though it might be able to someday, given how much information Google has control over). However, if one uses the official Google Translate extension for Google Chrome, one may actually translate only the selected text. It is possible then that it is instead the extension which inspired the comic’s feature. This comic not only illustrates such a feature, but implies that the “translated” thoughts are what’s actually going on behind posts of these types on social media, as if Randall can actually read those people’s minds somehow. If this implication is the intent of the comic, then Randall thinks that people who have “no filter” are actually insecure and that people who want “NO DRAMA” are actually afraid of upset comments. Alternatively, Randall hates people who post such things in their profiles, and therefore wants to belittle them in this comic as actually being insecure, rather than being as confident as their aggressive behavior implies. This explanation is corroborated by notable news near the comic’s publishing time (see below). The style of the profile showcased in the comic resembles the profiles of the popular social media website Twitter, which while the user is logged in, shows the user’s own profile on the left side of the page in a similar style to the comic, with their picture on the left side of their name, their Twitter handle under their name (which explains the extra line of text under what is presumably the name) and their “bio” right below those. The Twitter “bio” is a space usually used for the user to explain who they are. Common details about a person which are included in their “bio” are their profession, their personal interests and the products they have for sale. Some people also write about their personality, such as the one in the comic, which is quite outspoken and frank about her opinions. The title of this comic is “Defensive Profile”. “Defensive” is the opposite of “offensive”, which is a word that might be used to describe the contents of profiles which display such a warning as in the comic. However, the feature reveals the warnings to actually be defenses against behaviors that deeply bother the profile owner. The profile is thus proved to actually be “defensive” instead of “offensive”, at least regarding the warning text. [A profile on an unknown social media site is displayed. The profile picture is a close-up image of Megan. The profile reads:] I speak my mind and don’t care who I offend. No filter. [In the next panel, the text is highlighted, and a context menu has appeared. There is a mouse pointer on the option "View translation".] Copy Select all View translation [selected] Print [In the last panel, the profile text is updated:] I don’t understand why people keep getting mad at me and I’m using this pep talk to convince myself that’s okay.

Thermostat

Thermostat

https://www.xkcd.com/1912

https://www.explainxkcd.com/wiki/index.php/1912:_Thermostat

[Hairy, with a headset on, is sitting in an office chair at a desk with his hands ready on the keyboard of his computer.] Hairy: Tech support, how can I help you? [Cueball is on his smartphone while looking at a small blinking panel on the wall in front of him.] Cueball: The little LCD on my thermostat says Error: Android system recovery: Unrecognized boot volume "/MONTHLY ENERGY REPORT (1).DOC" [In a frame-less beat panel Hairy just stares at his screen with his hands on his lap.] [Back to Cueball, now with Hairy's reply coming from the smartphone in a box with a jagged arrow pointing to the smartphone.] Cueball: It's asking if I want to partition the volume. What should I do? Hairy (on the phone): Have you tried walking into the sea.

Hairy is working at a tech support office, and receives a call from Cueball . After the scripted greeting, Cueball, who has the most bizarre tech issues , tells Hairy that his thermostat – a single-purpose device used to control indoor heating and air conditioning – is showing an error screen from the Android operating system , and asking if he wants to partition the volume. The Android error seems to imply that it is trying to mount a file with .doc extension (likely a Microsoft Word document ) as the boot device . An added twist is the "(1)" in the filename, which is commonly appended when a user attempts to copy a file into a directory that already has a file with the same name. Furthermore, the extension .docx has been the default option from Microsoft Office 2007 onwards rather than the earlier .doc extension used in the comic, implying that the file is likely a rather old one. The error message suggests a system problem at a low level of the device. Not only is the operating system missing, but the device is trying to locate the operating system inside a Microsoft Word document, something that has little to do with regulation of temperature and probably has no way of getting onto the device in the first place, let alone being considered as a bootable file. This is so abnormal that Hairy is briefly struck silent and, upon recovering, he suggests Cueball walk into the sea as a form of suicide, rather than try to solve the issue. The title text elaborates that the situation is so absurd that it must be divine punishment, so Hairy does not want to try and help him for fear of invoking the wrath of whatever deity is issuing it. An example of such reasoning in literature can be found in the character of Aeolus in the Odyssey , who, having made an unsuccessful attempt to assist Odysseus by giving him a bag containing unfavorable winds, refused to provide further assistance on the grounds that the gods were clearly hostile to Odysseus. Part of the humor is in the problem being only a slight exaggeration of real software issues. The symptoms are unlikely, yet possible (a thermostat could be running Android and could generate a report as a .doc file; given some data corruption, the name of the .doc file could get into the boot script and a volume could appear unpartitioned). It would take an expert Android or Unix engineer to fix, particularly on an embedded device with no obvious way to connect remotely or attach a keyboard. In real life, it would probably be easier to just replace an embedded device whose software was this broken. This is explored further in 2083: Laptop Issues where throwing Cueball into the ocean is mentioned. Both comics could explain the original "computer problem link to oceans" comic 349: Success . [Hairy, with a headset on, is sitting in an office chair at a desk with his hands ready on the keyboard of his computer.] Hairy: Tech support, how can I help you? [Cueball is on his smartphone while looking at a small blinking panel on the wall in front of him.] Cueball: The little LCD on my thermostat says Error: Android system recovery: Unrecognized boot volume "/MONTHLY ENERGY REPORT (1).DOC" [In a frame-less beat panel Hairy just stares at his screen with his hands on his lap.] [Back to Cueball, now with Hairy's reply coming from the smartphone in a box with a jagged arrow pointing to the smartphone.] Cueball: It's asking if I want to partition the volume. What should I do? Hairy (on the phone): Have you tried walking into the sea.

A ?

A �

https://www.xkcd.com/1913

https://www.explainxkcd.com/wiki/index.php/1913:_A_%C3%AF%C2%BF%C2%BD

[A picture of a yellow post-it note with a handwritten message:] A ⍰ took out the trash but the dishwasher still needs to be run [Caption below the panel:] Apple can try to fix the autocorrect bug, but I've already incorporated it into my handwriting.

After the update to Apple's iOS 11.1 , many (though not all) iPhone users suffered from a strange bug, where the autocorrection changed any input of the single lowercase letter "i" to either "A" or "!" followed by a space and a Unicode variation selector 16 (U+FE0F, on iOS displayed as a question mark in a square). [1] Using a replacement character (U+FFFD) to approximate this display, the result of typing "i took" might be "A � took" or "! � took". In a handwritten text, the "�" symbol could then be mistaken for a censored word, signifying indignation against the person taking out the trash. This problem previously manifested as an "I" followed directly by the VS-16 "emojify character", turning them into an " �" without the "A". [2] The note in this comic is the equivalent of starting a text message with "i took out..." and triggering the iOS bug. The joke revolves around acceptance of the bug through repetition has influenced the writer's hand written style. The codes in the title text refer to "A �" and "! �" respectively. The text provides a way to keep the "bug" active with the U+FFFD approximation, (which can be realized through the use of a Cydia tweak) even after it is patched. Although this would have no practical use, it is still a fun way [ citation needed ] for iPhone users to keep the infamous bug fresh in everyone's mind, and to make sure that the Apple company never lives down the embarrassing incident. The statement in the title text "no update can never take this away from you" is a double negative , which is a considered non-standard grammatical use in modern English, although common in many dialects. Taking literally it could actually mean "any update can take this away from you". This may be a typo or a colloquial use, with the intended meaning to be "ever" instead of "never" with some exaggeration. [A picture of a yellow post-it note with a handwritten message:] A ⍰ took out the trash but the dishwasher still needs to be run [Caption below the panel:] Apple can try to fix the autocorrect bug, but I've already incorporated it into my handwriting.

Twitter Verification

Twitter Verification

https://www.xkcd.com/1914

https://www.explainxkcd.com/wiki/index.php/1914:_Twitter_Verification

[A bearded figure, depicting the Twitter CEO Jack Dorsey, is standing behind a podium with the blue Twitter bird logo.] Jack: Everyone calm down— Jack: We just need to go figure out how to bestow a global in-or-out status badge on some people, at our discretion, without anyone reading anything into who gets one. Jack: This should only take a moment.

Some Twitter users (such as Randall Munroe , Coldplay , and, prior to being suspended, Donald Trump) have a verification checkmark next to their name. This checkmark is used to indicate that the user is who they say they are, rather than being a fake account made by someone else using their picture and name. This helps fans find the real accounts of their favorite celebrities. However, since the most notable people benefit from this the most, there is some ambiguity in the granting of the verified mark, as it also seems to be interpreted as a status symbol to indicate the notable celebrities. Some even see this as Twitter actively endorsing the user. For this reason, Twitter has removed verified checkmarks from real accounts of celebrities because of political controversies in the past. Examples of this are political commentator Milo Yiannopoulos (before he was banned from the service). One recent controversial decision regarding the verified mark is that Twitter gave a verification checkmark to Jason Kessler , the organizer of a recent far-right rally in Charlottesville, Virginia. This drew attention to Twitter's verification system, so they temporarily suspended it. The alt-text comments on the lack of foresight on Twitter's part when implementing the verified system: as it by design separates users between an in-group and an out-group, it seems to imply endorsement or, at least, favors some users to the detriment of others. This in turn automatically creates the twin sets of "people who shouldn't have been verified, but were" and "people who deserve to have been verified, but weren't." As the internet is populated by various large and strongly opinionated groups [ citation NOT needed ] , neither set will ever be empty and Twitter will always be seen as either endorsing unworthy or snubbing worthy people. The last line of dialogue is a typical English sentence and has nothing to do with the Twitter Moments feature, which can be used to compile several tweets with a shared theme into a browsable gallery. The character depicted is the (at the time of publication) Twitter CEO Jack Dorsey , judging by the beard. [A bearded figure, depicting the Twitter CEO Jack Dorsey, is standing behind a podium with the blue Twitter bird logo.] Jack: Everyone calm down— Jack: We just need to go figure out how to bestow a global in-or-out status badge on some people, at our discretion, without anyone reading anything into who gets one. Jack: This should only take a moment.

Nightmare Email Feature

Nightmare Email Feature

https://www.xkcd.com/1915

https://www.explainxkcd.com/wiki/index.php/1915:_Nightmare_Email_Feature

[A panel with a short email message, with the first line partly obscured by the top of the panel. Below that, in light gray font, is an information message from the email client.] Enjoyed it! I'm busy this weekend, but let me know if you're free sometime next week and want to get dinner or something. Total time spent revising this email before sending: 47 minutes 12 seconds ... [Caption below the panel:] My nightmare email feature

Most modern email clients provide tools to help their users read, write, and keep track of email efficiently. For instance, the user may receive a notification if the email body contains wording that suggests a file has been attached, but there is no actual attachment, in order to prevent them forgetting to include the intended file in the email. This comic suggests a similar feature, one which would inform not the user, but the recipient of the message, how long the email has been revised before being sent. This is an expansion of a common feature of collaboration tools used by law firms, and modern word processors such as Microsoft Word 2016. Randall calls this his nightmare email feature, implying he spends too much time in revision of what should be simple email messages and that making himself - or worse, the recipient - aware of the actual time would make him anxious. In the case shown it seems that the sender and recipient of the e-mail had recently met, and the recipient suggested meeting again this weekend. It then took 47 minutes to write a short reply in which the sender ends up saying only that they enjoyed the thing referred to, but, alas, they have no time this weekend, and then lets the other suggest a possible time for a dinner... or something. Of course there could be more to the email above the panel, but it seems to be a very short answer to another e-mail, and it increases the nightmare for the writer (and the impact of the joke) if this was all that was written in 47 minutes. If the text had been written out in less than 2 minutes, it would not have been a problem, but it seems the writer of this e-mail had to think a lot about how it was phrased. This could lead the recipient to wonder what took so long. Was it that they did not enjoy it, but ended up writing this to be nice? They only write that they are busy this weekend, thus not giving any reason as to why, and the last part allows them the possibility of also being "busy" on whatever time is suggested for dinner. Also, "or something" is very non-committal. Alternatively it could be the opposite, for a case where the writer enjoyed the time a lot, and is really looking forward to another meeting, but tries to seem relaxed and open minded, to not scare the other person away. All of this would also be true if it had been written in 2 minutes, but then at least there would have been the excuse of not having spent a lot of time thinking about how the reply was phrased. The title text describes a similarly uncomfortable feature, which would inform the recipient how long a message has been sitting in the user's drafts folder, thus highlighting their procrastination, as well as demonstrating that "(...)didn't see your message until just now" is a lie, or at least it was only true when the original message was written, and now three days later another message should have been written instead. This feature would also be able to catch anyone who tries to avoid the feature depicted in the comic by saving the email in "drafts" while making revisions outside the mailing software, either mentally or in another word processing program. Randall has explored a related anxiety-inducing feature of instant messaging in 1886: Typing Notifications . Applying the feature in the comic to this explanation: it sat incomplete in this wiki for approximately 2 months and 26 days (since the comic's creation), before an unregistered user removed its incomplete tag. [A panel with a short email message, with the first line partly obscured by the top of the panel. Below that, in light gray font, is an information message from the email client.] Enjoyed it! I'm busy this weekend, but let me know if you're free sometime next week and want to get dinner or something. Total time spent revising this email before sending: 47 minutes 12 seconds ... [Caption below the panel:] My nightmare email feature

Temperature Preferences

Temperature Preferences

https://www.xkcd.com/1916

https://www.explainxkcd.com/wiki/index.php/1916:_Temperature_Preferences

[A chart labeled:] Where to live based on your temperature preferences [In gray, the data source is mentioned below:] Climate data from weatherbase.com [A chart with two lines with single arrows. Each arrow is labeled:] Y axis bottom: Cold winters X axis right: Hot/humid summers (measured via Humidex, which combines heat and dew point) [Near each of the corners of the chart there is a gray blob, labeled:] Top left: If you hate cold and heat Top right: If you hate cold and love heat Bottom left: If you love cold and hate heat Bottom right: If you love cold and heat [The following city names intersect with the top left blob [hate cold and heat] (in reading order):] Mexico City Quito Addis Ababa Bogotá San Francisco Wellington [The following city names intersect with the top right blob [hate cold and love heat] (in reading order):] Bangkok Ho Chi Minh City Manila Singapore Mumbai Jakarta Dar Es Salaam Honolulu Lagos Rio [de Janeiro] Dhaka Kinhasa Miami Karachi Dubai Cairo Hong Kong Delhi Riyadh Guangzhou Lahore Sabha Houston Needles El Paso Baghdad Dallas [The following city names intersect with the bottom left blob [love cold and hate heat] (in reading order):] Reykjavik (with arrow pointing left) Berlin Stockholm Oslo Calgary Halifax Daqaidam Kiev Casper Yumen St Petersburg Volgograd Moscow Ottawa Vladivostok Thunder Bay Duluth Urumqi Altay Regina Irkutsk Abakan Ulaanbaatar Blagoveshchensk (also on bottom right blob) Fairbanks McMurdo (with arrow pointing down-left) Yellowknife (with arrow pointing down) Hailar [The following city names intersect with the bottom right blob [love cold and heat] (in reading order):] [Washington] DC Shanghai Tehran Saint Louis New York Xi'An Salt Lake City Kansas City Beijing Seoul Sapporo Pyongyang Sioux Falls Turpan Jinzhou Minneapolis Shenyang Fargo Tongliao Qiqihar Blagoveshchensk (also on bottom left blob) [The following city names do not intersect with any blob (in reading order):] Nairobi São Paulo Brisbane Los Angeles Perth Cape Town Sydney Athens Santiago Barcelona Melbourne Rome Buenos Aires Jerusalem Atlanta Raleigh Madrid Chengdu Tokyo Dublin Portland Richmond London Istanbul Edinburgh Vancouver Paris Flagstaff Santa Fe Tashkent Wuhan Geneva Lubbock Boston Budapest Kabul Toronto Omaha

This is a chart of major (and not-so-major) populated areas showing seasonal temperature patterns. The chart is a guide to where one might like to live depending on how much summer heat and winter cold they enjoy. There are four focused zones: The summer heat axis is determined by humidex , a system that combines heat and humidity to generate an estimate of perceived "summer discomfort". Note that if the values from this table are charted, the result is similar but not exact to how Randall drew the comic. For instance, he shows Kinshasa as having a “colder” winter than Honolulu, but the average low in the coldest month for Kinshasa (20°C) is hotter than the average low in Honolulu (18.9°C). In general these differences are minor, but a few stand out: It is not certain if these differences are a due to errors, the use of a different data set, or deliberate “Easter Eggs” set to see if anyone would notice. According to Randall: However, given the great variability of weather patterns across the globe, it's not altogether clear how useful this would actually be to someone looking to choose where to live, since it's not clear exactly what "love/hate hot/cold" would mean. It's also not clear that the relationship between temperature and discomfort is linear. More likely is that there is a small temperature band where each degree of change causes significantly more discomfort, and beyond which it's just "too hot/cold". Hottest and coldest month therefore may not be the best measure. For example, is one or two very cold days better or worse than a month's worth of moderately cold days? Shown in the table below for each place are the number of days above 32°C (90°F) and the number of days below 0°C (32°F), taken from Weatherbase.com (Randall's source). For most people a temperature above 32°C is considered hot and a temperature below 0°C is considered cold. So, for instance, someone who loves heat might want to live in Tehran (with three months above 32°C) rather than Beijing (with only one month) even though the peak month Humidex in Beijing is higher. Someone who loves cold might want to live in Santa Fe, where it never gets particularly cold (only -8°C) but where it is below freezing almost half of the year (179.8 days on average). In general though, the places with the most hot or cold days also have the hottest and coldest extremes. Once again, Turpan stands out for its misery, with days above 32°C totaling four months and days below 0°C totaling four months. In fact, on average there is at least one day every month of the year that the temperature is either above 32°C or below 0°C. This includes almost every day in June, July and August being hot and every single day in December, January and February being below freezing. Some of the most extreme climates on earth are not shown on this comic, however, perhaps because some of them are uninhabited. Eismitte (a camp established in the center of Greenland in the 1930s) and Vostok Station (in the center of Antarctica) both see temperatures far colder than McMurdo, although being in the middle of ice caps neither can be inhabited without outside support. The areas around Oymyakon and Verkhoyansk in eastern Siberia also see temperatures colder than McMurdo and are actual towns, although summer temperatures are much higher. In both places the summer weather is generally average (Humidex of 22°C to 23°C) but they have seen record highs of 34°C to 37°C and record lows of almost -68°C, giving them the greatest temperature swings on earth. Bouvet Island is a small island in the South Atlantic Ocean, near the latitude where there are no land masses to interrupt storms and currents (south of South America but north of Antarctica). As a result it has one of the most consistent climates on earth, with a high and low almost always within a few degrees of 0°C all year long – a perpetual state of almost to just freezing, combined with clouds, fog, wind and rain from ocean storms. Death Valley in California, Shahdad in Iran, and Murzuk in Libya all vie for having the highest temperature in the world, although not the highest Humidex. The relevant temperature data for these extreme locations, where known, is in the second table for comparison. The title text refers to a quote sometimes attributed to Mark Twain ; however, as it points out, the quote is misattributed , and it is unknown who created it. The text then goes on to claim that the person who originally said the quote never visited McMurdo Station , a US Antarctic research center, which is certainly a colder place than San Francisco. The comic as originally published had a "smudge" or scattering of gray pixels, visible in the center of the image between the labels for Madrid and Lubbock. A new version of the image was later uploaded with this removed. By editing the image to increase the contrast between the background and the "smudge", as shown here, it is possible to see dots and grid lines. This would seem to be a scatter graph, likely one showing temperature data used by Randall as a reference while making this comic, and accidentally left visible when the comic was first uploaded. A similar thing happened in 1561: Water Phase Diagram , where a phase diagram from Wikipedia was faintly visible in the original version of the comic . [A chart labeled:] Where to live based on your temperature preferences [In gray, the data source is mentioned below:] Climate data from weatherbase.com [A chart with two lines with single arrows. Each arrow is labeled:] Y axis bottom: Cold winters X axis right: Hot/humid summers (measured via Humidex, which combines heat and dew point) [Near each of the corners of the chart there is a gray blob, labeled:] Top left: If you hate cold and heat Top right: If you hate cold and love heat Bottom left: If you love cold and hate heat Bottom right: If you love cold and heat [The following city names intersect with the top left blob [hate cold and heat] (in reading order):] Mexico City Quito Addis Ababa Bogotá San Francisco Wellington [The following city names intersect with the top right blob [hate cold and love heat] (in reading order):] Bangkok Ho Chi Minh City Manila Singapore Mumbai Jakarta Dar Es Salaam Honolulu Lagos Rio [de Janeiro] Dhaka Kinhasa Miami Karachi Dubai Cairo Hong Kong Delhi Riyadh Guangzhou Lahore Sabha Houston Needles El Paso Baghdad Dallas [The following city names intersect with the bottom left blob [love cold and hate heat] (in reading order):] Reykjavik (with arrow pointing left) Berlin Stockholm Oslo Calgary Halifax Daqaidam Kiev Casper Yumen St Petersburg Volgograd Moscow Ottawa Vladivostok Thunder Bay Duluth Urumqi Altay Regina Irkutsk Abakan Ulaanbaatar Blagoveshchensk (also on bottom right blob) Fairbanks McMurdo (with arrow pointing down-left) Yellowknife (with arrow pointing down) Hailar [The following city names intersect with the bottom right blob [love cold and heat] (in reading order):] [Washington] DC Shanghai Tehran Saint Louis New York Xi'An Salt Lake City Kansas City Beijing Seoul Sapporo Pyongyang Sioux Falls Turpan Jinzhou Minneapolis Shenyang Fargo Tongliao Qiqihar Blagoveshchensk (also on bottom left blob) [The following city names do not intersect with any blob (in reading order):] Nairobi São Paulo Brisbane Los Angeles Perth Cape Town Sydney Athens Santiago Barcelona Melbourne Rome Buenos Aires Jerusalem Atlanta Raleigh Madrid Chengdu Tokyo Dublin Portland Richmond London Istanbul Edinburgh Vancouver Paris Flagstaff Santa Fe Tashkent Wuhan Geneva Lubbock Boston Budapest Kabul Toronto Omaha

How to Make Friends

How to Make Friends

https://www.xkcd.com/1917

https://www.explainxkcd.com/wiki/index.php/1917:_How_to_Make_Friends

[First panel with words, with the words in the center white and on a black oval background, which is in turn on the white background:] Presenting: How to make friends [Second panel with Cueball and Hairy facing each other:] Cueball: Want to go eat food together? Cueball: We could also sit together and talk without eating. I don't need to eat. I mean, I do need to eat. But if you don't want to eat then we can just talk. I can eat later. [Third panel with words, same format as first panel:] Okay It turns out I still haven't figured out how to do this. Sorry

This comic follows a sample interaction, purportedly showing how to make friends. We see Cueball 's strategy for making friends. It does incorporate various points of advice for building friendships, which are completely sound in the abstract. But it's clearly not helping him -- he's out of sync with the interaction context and makes bigger social gaffes by following the abstract advice. Escalating awkwardness ensues. It starts out with a common way of making friends or interacting with friends, hanging out over a meal. However, Cueball suggests doing so with awkwardly literal phrasing; whereas most people use expressions such as “have lunch” or “grab a bite to eat”, Cueball explicitly invites Hairy to “eat food”. The fact that he feels the need to clarify that they’ll be eating food, as opposed to any other orally consumable items, indicates his lack of confidence to clearly communicate his intentions. Before Hairy can even respond, Cueball then says that they could instead “sit together and talk without eating.” Although this is indeed another common way to make friends, it’s kind of an odd way to phrase it, especially since he didn’t even give Hairy a chance to reply to his initial suggestion. Cueball then says he doesn’t need to eat (meaning not right now , especially as a prerequisite to talking), but he immediately feels compelled to clarify that he does need to eat (meaning in general ). Again, it’s weird that he clarified, as his original wording probably would have been understood. He then awkwardly remarks about how he can eat later if Hairy would rather just talk. The overall implication is that Cueball’s awkwardness and over-explanation would put off a typical person, although some people find it endearing . This is a situation that Randall has encountered before, in 1746: Making Friends , in which he offered "advice" to play dead to attract new friends and/or turkey vultures; presumably he has "learned" from his unsuccessful attempts and is trying more conversational approaches, but apologizes to the reader as he hasn't quite figured that out either. The title text says Cueball wants to be friends at Hairy, rather than with him, which isn’t how friendship usually works. “At” implies that Cueball considers being friends to be a unilateral action that he needs to direct towards Hairy, like “smiling at” or “pointing at”, and does not understand that it is typically a mutual activity of building a relationship, which would be indicated by being friends with him. “At” can even carry a degree of animosity (compare: “he just phoned up to wash his head at us” ). [First panel with words, with the words in the center white and on a black oval background, which is in turn on the white background:] Presenting: How to make friends [Second panel with Cueball and Hairy facing each other:] Cueball: Want to go eat food together? Cueball: We could also sit together and talk without eating. I don't need to eat. I mean, I do need to eat. But if you don't want to eat then we can just talk. I can eat later. [Third panel with words, same format as first panel:] Okay It turns out I still haven't figured out how to do this. Sorry

NEXUS

NEXUS

https://www.xkcd.com/1918

https://www.explainxkcd.com/wiki/index.php/1918:_NEXUS

[Megan and Cueball walking through an airport.] Sign: Apply for NEXUS Save time at the border Megan: Maybe we should sign up for this. Cueball: No way. I refuse to have anything to do with Nexus after what they did to FernGully.

Cueball is confusing NEXUS , a USA and Canada border control pre-screening program , with Hexxus , the villains from the animated film FernGully . Trusted traveller programs like Nexus allow people who match certain criteria to apply for a membership and subsequently save time when boarding airplanes or crossing borders via use of expedited lanes. FernGully is a story set in an Australian rainforest inhabited by fairies including Crysta, who accidentally shrinks a young logger named Zak to the size of a fairy. Together, they rally the fairies and the animals of the rainforest to protect their home from the loggers and a malevolent pollution entity, Hexxus. Hexxus has previously been mentioned in 1750: Life Goals as an especially hard-to-spell word and in 1767: US State Names (as a replacement for Texas). The title text is confusing Cisco (a telecoms & tech brand which has a line of switches called Nexus ) with: [Megan and Cueball walking through an airport.] Sign: Apply for NEXUS Save time at the border Megan: Maybe we should sign up for this. Cueball: No way. I refuse to have anything to do with Nexus after what they did to FernGully.

Interstellar Asteroid

Interstellar Asteroid

https://www.xkcd.com/1919

https://www.explainxkcd.com/wiki/index.php/1919:_Interstellar_Asteroid

[Megan walks towards Cueball while looking at her phone. Cueball sits in front of his laptop.] Megan: Hey, you know that asteroid that tumbled past from another star system? It's apparently really long and skinny. Megan: Like a ratio of 6:1 or 10:1. Cueball: Weird. Wonder what it's shaped like. [Megan lowers her phone and looks up. Cueball looks backward.] Megan: Without more data, it would be irresponsible to speculate further. Cueball: So...you're going to? Megan: Absolutely. [Frameless panel focusing on Megan.] Megan: Here are some objects with a similar shape ratio: Megan: The 1:4:9 monolith from 2001: A Space Odyssey . Megan: A star destroyer. Megan: A huge eggplant emoji. [Same setting with Megan and Cueball.] Megan: A statue of Weird Al. An iPhone XXXXX. Voltron. Megan: A giant space coffin. But who could be inside? We can only guess. I'll start: Cueball: This is all based on how many data points, again? Megan: One. But it's a perfect fit!

ʻOumuamua is the first detection of an interstellar asteroid passing through the Solar System originating from another solar system. Megan 's list of objects with a similar shape ratio: As soon as Megan lists off the last item, she is about to start speculating within her own speculative scenario about who or what might be in the coffin before Cueball interrupts her. Cueball attempts to bring Megan back down to earth by reminding her that she has too little data to work with (one data point), but Megan is far too excitable to listen to reason. A good example of the dangers of speculating irresponsibly, it would seem. It could also be argued that Megan with this makes fun of many news outlets whose first reaction to a new space body often seems to be to search for something to compare its shape to, such as with the 'rubber duck' comet . Making fun of media covering science news is a recurring theme on xkcd. The title text suggests taking reciprocal action by sending asteroids away when the solar system receives them. This would, of course, be difficult, given the amount of energy needed to shift asteroids outside of the Sun's gravity hold. On top of that, it appears to imply that some non-human entity is sending these rocks, which is an inane idea. This could be a reference to the movie Starship Troopers , where a race of aliens mankind is at war with supposedly hit Earth with asteroids. Given that a typical interstellar traveler -- like the one spotted now in real life -- spends millions of years getting from one star system to another, the movie's idea is plain stupid; in fact, the movie gives no proof the aliens were actually responsible, leading to a common fan theory that the asteroid was indeed random space junk and the aliens are being framed by the human government as pretense for war. [Megan walks towards Cueball while looking at her phone. Cueball sits in front of his laptop.] Megan: Hey, you know that asteroid that tumbled past from another star system? It's apparently really long and skinny. Megan: Like a ratio of 6:1 or 10:1. Cueball: Weird. Wonder what it's shaped like. [Megan lowers her phone and looks up. Cueball looks backward.] Megan: Without more data, it would be irresponsible to speculate further. Cueball: So...you're going to? Megan: Absolutely. [Frameless panel focusing on Megan.] Megan: Here are some objects with a similar shape ratio: Megan: The 1:4:9 monolith from 2001: A Space Odyssey . Megan: A star destroyer. Megan: A huge eggplant emoji. [Same setting with Megan and Cueball.] Megan: A statue of Weird Al. An iPhone XXXXX. Voltron. Megan: A giant space coffin. But who could be inside? We can only guess. I'll start: Cueball: This is all based on how many data points, again? Megan: One. But it's a perfect fit!

Emoji Sports

Emoji Sports

https://www.xkcd.com/1920

https://www.explainxkcd.com/wiki/index.php/1920:_Emoji_Sports

New sports created from random emoji [Man Playing Water Polo + Volcano] 🤽‍♂️🌋 Lavaball [Woman Playing Handball + Person Fencing] 🤾‍♀️🤺 Bladeball [Woman Dancing (2 emojis) + Soccer Ball] 💃💃⚽ Fancyball [Hole + Horse Racing (3 emojis)] 🕳️🏇🏇🏇 Horse hole [Kitchen Knife + Basketball + Pick] 🔪🏀⛏️ Basketball shredding [Egg + Telescope + Woman Detective] 🥚🔭🕵️‍♀️ Eggspotting [Skier + Crocodile] ⛷️🐊 Alligator jumping [Woman + Fishing Pole + Merman] 👩🎣🧜‍♂️ Merfishing [Man + Badminton + Fairy + Badminton + Woman] 👨🏸🧚🏸👩 Tinkerball [Curling Stone + Hedgehog + Curling Stone] 🥌🦔🥌 Hedgehog curling [Clamp + Hamburger] 🗜️🍔 Burger clamping [Woman Astronaut + Bow and Arrow + Satellite] 👩‍🚀🏹🛰️ Consequence archery [Owl + Right Arrow + Open Mailbox] 🦉➡️📬 Owlstuffing [Fork and Knife + Candle + Fork and Knife] 🍴🕯️🍴 Candle eating [Flag in Hole + Bomb + Woman Golfing] ⛳💣🏌️‍♀️ Consequence golf [Pointing Right + Snake + Pointing Left] 👉🐍👈 Snake shaming [Fire + Woman Climbing + Fire] 🔥🧗‍♀️🔥 Hell escape [Video Game + Avocado + Video Game] 🎮🥑🎮 Multiplayer avocado

This comic, as the heading indicates, arbitrarily selects emoji and uses them to make up very bizarre sports. Although some of these might be completely normal, most of them take things to a completely absurd level. The title text is a reference to the Triple Crown , which is an highly prestigious award given to a three-year-old thoroughbred horse who wins the Kentucky Derby , the Preakness Stakes , and the Belmont Stakes , the first three of the four listed events. The joke is that if Horse Hole was a real sport, then one who won a major competition for it, the Missouri Horse Hole, in addition to the three main horse racing events, would win a "Quadruple Crown". Please note that some emoji may not be supported by your browser, in which the emoji will appear as a black rectangle, and if there is a male/female version of the emoji, a male/female sign will appear next to the rectangle. New sports created from random emoji [Man Playing Water Polo + Volcano] 🤽‍♂️🌋 Lavaball [Woman Playing Handball + Person Fencing] 🤾‍♀️🤺 Bladeball [Woman Dancing (2 emojis) + Soccer Ball] 💃💃⚽ Fancyball [Hole + Horse Racing (3 emojis)] 🕳️🏇🏇🏇 Horse hole [Kitchen Knife + Basketball + Pick] 🔪🏀⛏️ Basketball shredding [Egg + Telescope + Woman Detective] 🥚🔭🕵️‍♀️ Eggspotting [Skier + Crocodile] ⛷️🐊 Alligator jumping [Woman + Fishing Pole + Merman] 👩🎣🧜‍♂️ Merfishing [Man + Badminton + Fairy + Badminton + Woman] 👨🏸🧚🏸👩 Tinkerball [Curling Stone + Hedgehog + Curling Stone] 🥌🦔🥌 Hedgehog curling [Clamp + Hamburger] 🗜️🍔 Burger clamping [Woman Astronaut + Bow and Arrow + Satellite] 👩‍🚀🏹🛰️ Consequence archery [Owl + Right Arrow + Open Mailbox] 🦉➡️📬 Owlstuffing [Fork and Knife + Candle + Fork and Knife] 🍴🕯️🍴 Candle eating [Flag in Hole + Bomb + Woman Golfing] ⛳💣🏌️‍♀️ Consequence golf [Pointing Right + Snake + Pointing Left] 👉🐍👈 Snake shaming [Fire + Woman Climbing + Fire] 🔥🧗‍♀️🔥 Hell escape [Video Game + Avocado + Video Game] 🎮🥑🎮 Multiplayer avocado

The Moon and the Great Wall

The Moon and the Great Wall

https://www.xkcd.com/1921

https://www.explainxkcd.com/wiki/index.php/1921:_The_Moon_and_the_Great_Wall

[Megan is holding her arm up towards Ponytail as they stand atop a large brick wall with merlons along the top. They are standing to the left of a tower with three small windows as well as merlons on the top.] Megan: Did you know that the moon's craters and plains are the only structures on the surface of a celestial body that can be seen with the naked eye from the Great Wall of China?

This is a reference to the myth that the Great Wall of China is the only manmade object [ citation needed ] that can be seen from the Moon (or from space) with the naked eye. Sadly, it cannot . In fact, it's barely visible from the orbit of low satellites. This comic mocks the myth by conflating it with another saying about the Moon, and how the Moon's craters and valleys are visible to the naked human eye. Indeed, the Moon is the only celestial body for which this is true, as all other bodies (with the potential exception of the Sun, see the title text) can only be seen as tiny points of light by the unaided human eye. There is nothing special about the Great Wall of China in this factoid, though; the Moon’s features can be seen equally well from practically any place on Earth with a view of the Moon. [ citation needed ] The title text states that one is sometimes able to see large sunspots if any are present and conditions are ideal. However, looking directly at the sun with the naked eye risks extensive damage to the eye and should NEVER be done. It could, however, be possible to see them when the Sun is seen through a thin cloud cover or maybe at sunset/sunrise. (It's possible to see very large sunspots with solar eclipse glasses or other adequate protection , but that's not unaided human eye.) [Megan is holding her arm up towards Ponytail as they stand atop a large brick wall with merlons along the top. They are standing to the left of a tower with three small windows as well as merlons on the top.] Megan: Did you know that the moon's craters and plains are the only structures on the surface of a celestial body that can be seen with the naked eye from the Great Wall of China?

Interferometry

Interferometry

https://www.xkcd.com/1922

https://www.explainxkcd.com/wiki/index.php/1922:_Interferometry

[Cueball is walking behind Beret Guy, who is walking two small dogs on two leashes.] Beret Guy: Interferometry. Is so cool! [They stop and Beret Guy is holding the leashes in his hand. He has taken them off the dogs and points at the dogs, which he has placed facing outward so they are standing a couple of paces apart. The distance between them is indicated by a labeled line.] Beret Guy: If you put two small dogs a large distance apart, they can function as a single giant dog. Line: d [Cueball begins to speak but is cut off by Beret Guy yelling as he jumps into the space above the two dogs, with each leg a good distance above one of the dogs. (The leashes have disappeared, as well as the distance line).] Cueball: I'm not sure that's- Beret Guy: Hyah! [As Cueball watches, Beret Guy floats on top of the invisible giant dog about a meter above the two small dogs, and then rides away with the two small dogs still seen below as they run to the right, leaving Cueball standing in the dust the "big" dog creates in its wake. The invisible giant dog barks from a position just in front of Beret Guy's face, far above the two small dogs.] Invisible giant dog: WOOF Beret Guy: Away!

Interferometry is the practice of overlapping two different waves to get a different signal, which can be used to determine the distance between two reflecting surfaces. An astronomical interferometer uses this principle to build an array of separate telescopes that are able to work together as a single telescope, effectively providing higher resolution using a process known as aperture synthesis . In the comic, Beret Guy and Cueball are walking Beret Guy's dogs when Beret Guy makes a comment on how interferometry is really cool. Beret Guy states that two dogs placed at a consistent interval will function as a larger dog — a play on the astronomical interferometer. While this idea works on waves, it probably won't work on dogs [ citation needed ] (though since h/p=λ it might), which is why Cueball is confused and starts to correct him. Before he can respond, however, Beret Guy jumps on his "large" dog and appears to be floating in midair. The existence of large dog is further proven when it gives out a large bark. Cueball looks on speechless while Beret Guy appears to exhibit another of his strange powers . In 1614: Kites , Beret Guy is "walking" a dog. It is possible that one of the dogs in this comic is the dog from Kites. The title text states that the effective giant dog is not any more 'good' than the two original dogs. This is analogous to sensitivity for astronomical interferometers. Interferometry does not increase the light-gathering area, so it cannot view dim objects as well as a single large telescope could. This is also a reference generally to dog-owners calling their dogs "good dog" or "good boy/girl" when they behave well; presumably, Beret Guy's giant interferometry dog is only as well-behaved as the dogs they are derived from. (However, as interferometry does collect more light than any individual telescope used, the interferometry dog is presumably more good than either individual dog. Considering the destructive potential of a giant bad dog, this is a good thing.) It may also be a reference to the They're Good Dogs, Brent meme. [Cueball is walking behind Beret Guy, who is walking two small dogs on two leashes.] Beret Guy: Interferometry. Is so cool! [They stop and Beret Guy is holding the leashes in his hand. He has taken them off the dogs and points at the dogs, which he has placed facing outward so they are standing a couple of paces apart. The distance between them is indicated by a labeled line.] Beret Guy: If you put two small dogs a large distance apart, they can function as a single giant dog. Line: d [Cueball begins to speak but is cut off by Beret Guy yelling as he jumps into the space above the two dogs, with each leg a good distance above one of the dogs. (The leashes have disappeared, as well as the distance line).] Cueball: I'm not sure that's- Beret Guy: Hyah! [As Cueball watches, Beret Guy floats on top of the invisible giant dog about a meter above the two small dogs, and then rides away with the two small dogs still seen below as they run to the right, leaving Cueball standing in the dust the "big" dog creates in its wake. The invisible giant dog barks from a position just in front of Beret Guy's face, far above the two small dogs.] Invisible giant dog: WOOF Beret Guy: Away!

Felsius

Felsius

https://www.xkcd.com/1923

https://www.explainxkcd.com/wiki/index.php/1923:_Felsius

[A thermometer is shown where the temperature is indicated, with a red column of liquid, to be just above room temperature. This can be seen from the five labels belonging to five lines pointing at the scale. None of these coincide with the 14 ticks on the actual scale for the thermometer. Below the last label is the formula for calculating the temperature on this scale.] 92°⋲ world heat record 68°⋲ body temperature 47°⋲ room temperature 16°⋲ water freezes –9°⋲ 0°F °⋲=7×°C/5+16=(7×°F–80)/9 [Caption below the panel:] Since the Celsius vs Fahrenheit debate has proven surprisingly hard to resolve, as a compromise I've started using Felsius (°⋲), the average of the two. An implementation of Felsius is available at Weather In Felsius , using a location based on user's IP address and accepting US ZIP codes (permanent dead link).

Just like in 1292: Pi vs. Tau , Randall tries to unify two measurement systems by averaging both values, with little success (however this is a matter of opinion). There are several temperature scales actively used in different parts of the world of for different purposes, including Celsius and Fahrenheit , but e.g. also Kelvin and Rankine . The debate on whether to use Fahrenheit or Celsius is, just like the one between United States customary units (which uses Fahrenheit), imperial units (outdated system that used Fahrenheit), and metric units (which use Celsius or Kelvin), one that is mostly restricted to the US. While Fahrenheit is a widely used temperature scale in the US, most other countries have already switched from Fahrenheit to Celsius or have always used Celsius. In scientific circles, even in the US, only Celsius (and Kelvin) are used. The conversion factors between Celsius and Fahrenheit are: °C = (°F − 32) × 5 / 9 °F = °C × 9 / 5 + 32 which makes the average (mean) value of °C and °F: °⋲ = °C × 7 / 5 + 16. The step-by-step derivation of this is: °⋲ = (°C + °F) / 2 = (°C + (°C × 9 / 5 + 32)) / 2 = (°C + °C × 9 / 5 + 32) / 2 = (°C × 5 / 5 + °C × 9 / 5 + 32) / 2 = (°C × (5+9) / 5 + 32) / 2 = (°C × 14 / 5 + 32) / 2 = °C × 7 / 5 + 16 Randall chose to name his new unit of temperature Felsius (a portmanteau of Fahrenheit and Celsius). Comically enough, the Felsius scale discards the main advantages of either temperature scale. The Celsius scale is based around 0 °C as the melting point of water and 100 °C as the boiling point, which is an advantage Felsius does not preserve. Fahrenheit is often argued to be a convenient temperature measure for human comfort, as 0 °F is very cold and 100 °F is very hot. Many places on earth which humans inhabit fall reasonably well within these extremes the majority of the time, but Felsius does not preserve this advantage of the Fahrenheit scale either. The title text states that the symbol he chose to represent this unit also is the average of two other symbols. Visually, it is assumed to be a combination of Celsius and Fahrenheit (a C with a crossbar), but it is actually the unrelated symbols for the euro (€) and the Greek lunate epsilon (ϵ). Randall's symbol has a single crossbar, like the Greek lunate epsilon, but the crossbar continues to the left, like the Euro symbol. (In this explanation and the transcript, we have used the mathematical symbol U+22F2 , which may appear too large or too small depending on the font.) In doing all this, Randall has fallen into the trap of creating a new temperature scale/standard: see 927: Standards . Randall has also compared Celsius and Fahrenheit scales earlier in 1643: Degrees and in 526: Converting to Metric he tries to give users of the Fahrenheit scale an idea about what a given Celsius temperature would feel like. This is an example of Argument to Moderation , also known as the false middle point fallacy. A famous use of this fallacy is in the Bible, the Judgment of Solomon . The true mother of a disputed baby is discovered [1] by proposing the "compromise" of cutting the baby in half. Perhaps Randall has a similar strategy in proposing Felsius, an absurd compromise, in order to somehow discover the "true" temperature scale. Note that this is not the first time Randall has proposed a controversial third way . [A thermometer is shown where the temperature is indicated, with a red column of liquid, to be just above room temperature. This can be seen from the five labels belonging to five lines pointing at the scale. None of these coincide with the 14 ticks on the actual scale for the thermometer. Below the last label is the formula for calculating the temperature on this scale.] 92°⋲ world heat record 68°⋲ body temperature 47°⋲ room temperature 16°⋲ water freezes –9°⋲ 0°F °⋲=7×°C/5+16=(7×°F–80)/9 [Caption below the panel:] Since the Celsius vs Fahrenheit debate has proven surprisingly hard to resolve, as a compromise I've started using Felsius (°⋲), the average of the two. An implementation of Felsius is available at Weather In Felsius , using a location based on user's IP address and accepting US ZIP codes (permanent dead link).

Solar Panels

Solar Panels

https://www.xkcd.com/1924

https://www.explainxkcd.com/wiki/index.php/1924:_Solar_Panels

[A flow chart that features four questions in bubbles. Each question has yes/no options in bubbles overlain to the left and right on the question bubble. Curved arrows points from the yes and no bubbles to either the next question or the result. The result written at the bottom is not inside bubbles. The chart has two main branches, that ends up in five places using only four different results, as the middle result is shared by both branches. Above the chart, there is a caption:] Should I put solar panels on it? Does it move around? Yes Does it have regular chances to recharge or swap batteries? Yes Probably not No When running, is it hot to the touch? No Maybe Yes Haha good luck No Is there an empty space nearby where it would be easier to put them? Yes Probably not [Uses the same sentence as the one in the first branch.] No Sure

This handy decision tree aims to help in finding out whether a given object should have solar panels installed on it. The root question is whether the object of choice moves. If it doesn't and has no nearby empty space that would be more practical for the solar panel installation, then yes, the object should be equipped with the solar panels. If the object is static, but you could more easily install the panels somewhere else nearby, probably that's the best place. An example of this is a slanted rooftop of a house or a field on a hillside: it's certainly possible to put solar panels there, but if a flat surface, like a flat-roofed house or a level field, is available, it would generally be easier to put them on that. This way, you can select the optimal direction for the panels to face, which might not be possible on a given incline, or even have them move to track the sun . However, if the house has a side that is turned towards the sun (south in the Northern hemisphere) then a house roof could be even better than on the ground, which is why the title text says "sure" for rooftops. For another example of things where "putting next to it" instead of "on it" is generally the easier (and arguably better) option, see the "highway surfaces" of the title text. If the object moves, the next question is whether its batteries can be recharged or swapped with ease, in which case batteries may be a better option than solar panels, if the purpose of the panels is to power the object. The idea is that solar panels on a vehicle sound like an interesting idea, but batteries can be much more easily (and economically) recharged from a fixed electrical station than using solar panels on the vehicle as a power source. It may be possible to have solar panels on the electrical station , but that is a separate device to consult the table on. Finally, if the object moves and batteries are not an option, the last question is whether the object heats up during operation. If so, solar panels may not work well. Randall doubts it mockingly, see also the title text regarding his Haha Good luck final option. Solar panels can only produce electrical power equal to about 20% of the solar radiation they receive. Thus, a device that heats up during use likely consumes much more power than the amount which could be produced by solar panels covering its surface - so "good luck". Obviously, many animals are also "moving objects" fitting this condition, and installing solar panels on them is bound to be a challenge. Moreover, solar panels do not work effectively when excessively hot [1] (solar panels are typically designed to operate in temperature ranges of 15-25 Celsius, 59-77 Fahrenheit, 288.15-298.15 Kelvin, 518.67-536.67 Rankine, 12-20 Réaumur, 15.38-20.63 Rømer, 127.5-112.5 Delisle, 4.95-8.25 Newton, 5.968 546×10⁻²¹ - 6.174 608×10⁻²¹ joules of translational kinetic energy or 37-51 Felsius ). But if changing batteries is not an option, and heat production and power requirements are low, then solar panels can be an excellent solution on a moving object. An excellent case for this is on space probes and satellites, which are typically powered entirely by solar panels (and reliably receive sunlight, because there are no clouds to interfere). Randall is well aware of this, as shown with the comics 695: Spirit and 1504: Opportunity about the two solar-powered Mars rovers , although in this comic he seems to have only been concerned with Earthbound objects. The flow chart, however, does not mention if the thing in question actually needs solar panels, but according to the title text it works very well, and thus Randall implies that if the answer is sure then it is relevant to put solar panels there. The more solar panels in place, the fewer fossil fuels are needed, and this is in line with Randall's general interest in reducing climate change . The title text suggests that this flow chart is very broadly applicable to anything the Sun hits. Rooftops are classed as "sure", and those are, indeed, an active subject of solar installation (though, if there's suitable land nearby, it might not be the most efficient). Highway surfaces are classed as "probably not". There have been proposals and experiments a concerning photovoltaic pavement covering roadways with solar panels , but these have proven to be impractically expensive and prone to damage. The flow chart suggests that, since many highways are near land that could be used for solar panels, that will usually be the more viable option. Sailboats are classed as "maybe". Unlike boats with motors, sailboats don't consume enough power to heat up, only requiring enough power to provide electricity for whatever equipment and appliances are on board. Since some sailboats are at sea long enough that swapping or recharging batteries may be difficult, solar panels could be a viable option. Multiple other moving objects, including jets, cars, and wild deer ends up on the haha good luck result. While these examples seem unrelated, they all have the same limitation: they consume far more power while moving than could realistically be harnessed from solar panels (as demonstrated by the fact that they noticeably heat up). There are some experimental solar-powered cars, but these tend to be exceptionally low power (and resultingly low-performance) vehicles. Wild deer are clearly a humorous option, as they'd have little use for the electricity from solar panels, and would likely resist any efforts to install them. Nonetheless, Randall includes them to make the point that the chart is effective, even with ridiculous examples. [A flow chart that features four questions in bubbles. Each question has yes/no options in bubbles overlain to the left and right on the question bubble. Curved arrows points from the yes and no bubbles to either the next question or the result. The result written at the bottom is not inside bubbles. The chart has two main branches, that ends up in five places using only four different results, as the middle result is shared by both branches. Above the chart, there is a caption:] Should I put solar panels on it? Does it move around? Yes Does it have regular chances to recharge or swap batteries? Yes Probably not No When running, is it hot to the touch? No Maybe Yes Haha good luck No Is there an empty space nearby where it would be easier to put them? Yes Probably not [Uses the same sentence as the one in the first branch.] No Sure

Self-Driving Car Milestones

Self-Driving Car Milestones

https://www.xkcd.com/1925

https://www.explainxkcd.com/wiki/index.php/1925:_Self-Driving_Car_Milestones

Upcoming and recently-achieved Self-driving car milestones Automatic emergency braking Highway lane-keeping Self-parking Full highway autonomy First sex in a self-driving car Full trips with no input from driver Full trips by empty cars An empty car wandering the highways for months or years until someone notices the credit card fuel charges Cars that read other cars' bumper stickers before deciding whether to cut them off Autonomous engine revving at red lights Self-loathing cars Autonomous canyon jumping Cars capable of arguing about the trolley problem on Facebook

With the creation of self-driving cars, many new milestones are being found and/or solved thanks to them. Some are good, and some are downright weird. This comic lists some that have already been achieved, some that are being worked on and some that are facetious "milestones". Automatic emergency brakes This is another reference to how hard it can be to program human-obvious stuff (as in 1425: Tasks ). A self-driving car has to be able to distinguish a danger (cliff, person on foot/cycle/etc., other cars coming the wrong way/doing weird stuff) from the side of the road, the background, the other cars, or even a light pole safely standing on the side of the road. Then the car also has to decide the optimal response, taking into account weather conditions, road type and traffic - whether to turn aside, just slow down (as danger is not imminent), or actually do the strong brake. There are big potential advantages for self-driving cars if this problem can be solved: computers don't tend to panic as much as humans, would have faster reaction times and would have more reliable judgment . Highway lane-keeping Sometimes, especially on highways where road delimitations might be faint or absent , or when lane markings could have faded away, a self-driving car programmed to pilot based on road markings would have issues holding to the correct side of the road. This is a bigger problem on highways than in cities, as cars move faster on highways, so the danger detection mentioned above might not manage to detect danger in time, while braking or avoiding the obstacle needs to be anticipated much more. Self-parking Already implemented in recent normal cars, this feature is important to remove the car from the road while not in use, and is sometimes considered a difficult maneuver for drivers to master, as it requires a good "feeling" of the car dimensions, as well as of distances and maneuverability of the car, and also information about surrounding barriers. The latter parameters, being easy to sense with radar and back-camera aide, are made more reliable with computers. Full highway autonomy The ability for a car to drive itself on a highway. As of 2017, there are plans under consideration to set highway lanes aside for self-driving cars, but this milestone would require a car to be able to operate on a highway that also has human-driven cars, as well as wildlife, pedestrians, debris and other obstacles, should they enter the highway. First sex in a self-driving car This is not a milestone for the cars themselves, but just the age-old practice of having sex in cars, performed in a car that happens to be self-driving. Given the nature of human sexuality, it is probable that this had already happened at the time of this comic. The first public documentation of this milestone was published in May of 2019, as a video featuring coitus occurring in a Tesla Model X on autopilot went viral on PornHub. Full trips with no input from driver The main point of self-driving cars, allowing all humans within to act as passengers. As of 2017, self-driving cars require a human to be able to take over just in case, but any such trip where the human never actually took control would qualify for this milestone. However, there could be an additional joke here that the car is driving without human input including the destination. In this case, the car itself is choosing where to go, leaving the humans helpless. Full trips by empty cars A more complete version of the above, since with no humans present, no human can take control. This could be considered fulfilled by the DARPA Grand Challenge entrants, as the challenges are racing competitions of autonomous cars with no humans on board. Possibly a reference to 1559: Driving . Self-refueling of empty cars This would require either: a robotic fuel station, able to refuel cars with humans inside as well; an ordinary full-service fuel station (that is, one where the station's employee performs the refueling of the car) that happens to service a self-driving car with no humans aboard (which could be arranged as a publicity stunt); a specially designed fuel station that would allow self-driving cars to refuel by docking to it (likely to require fine control of the docking procedure that would render it unsuitable for more fallible human-driven cars); or, perhaps least likely, a robotic arm attachment on the car that would allow it to use a normal self-service fuel station. Currently Tesla's robotic charging station is the closest thing to this accomplishment. It is most certainly a reference to 1559: Driving . An empty car wandering the highways for months or years until someone notices the credit card fuel charges Cars are expensive enough that, were one to drive itself off and wander, some effort would be made to track it down. As this would require the self-refueling milestone, local fuel stations could be alerted to look for the "rogue" car—and in any case, whatever payment method is used to pay for the fuel would be traced. Cars that read other cars' bumper stickers before deciding whether to cut them off Another facetious milestone, implying self-driving cars might obtain the capacity to hold and act upon opinions that might override safety and efficiency of transit. This would be generally considered undesirable [ citation needed ] , so this seems unlikely to actually happen, except perhaps as an unintended consequence of runaway self-learning. Autonomous engine revving at red lights Mimicking the human practice. This is often done by human drivers who wish to draw attention to their car and then speed off as quickly as possible once the light turns green, but is regarded by most as being a nuisance. As such, this is an unlikely goal for self-driving cars to achieve. Self-loathing cars This would require cars to become sentient enough to understand, and have negative opinions about, themselves. Depending on one's definition, though, self-diagnostic software might qualify, as they would be running on a car's computer and could express a negative opinion about the car (albeit normally limited to the context of the car needing maintenance). Autonomous canyon jumping Although it seems unlikely that a navigation routine would ever decide that jumping a canyon is part of an optimal route, a car could be programmed to jump a canyon as part of a stunt or show, with no human driver (or any other human aboard) at the time of the jump. It is questionable how "autonomous" such a car would be, though. Could also be a reference to the next point, with another popular setting in the discussions mentioned below: "should a self-driving car leave the road and drive into a canyon, which will kill the driver (and passengers), or stay on the road and kill others?". Possibly a reference to when a Tesla was driven off a cliff and the driver and his passenger survived without injury. The car was not on autopilot at the time. Could also be a reference to the previous point where the car develops enough self-loathing to want to commit suicide. Or it may be a reference to certain Knight Rider episodes. Cars capable of arguing about the trolley problem on Facebook The Trolley problem is a well-known thought experiment in ethics, in which a person must choose between passively allowing several people to die or actively causing a single person to die. With the increasing likelihood of fully autonomous vehicles, there's been a flurry of interest in this problem, centered around what a vehicle should be programmed to do in such a case (for example, if avoiding a high-speed collision required running over a pedestrian). Munroe seems to mock this debate by arguing that the true milestone would not be when the vehicle can make such a decision, but when it can argue about it on Facebook. This may refer to the idea that humans aren't capable of agreeing on a resolution to the problem, so expecting a vehicle to resolve it would be less reasonable than expecting it to be able to debate. On the day this comic was released the Youtube channel Vsauce posted a video, The Greater Good - Mind Field S2 (Ep 1) , where they tested people's reactions to the trolley problem in a fake situation where the subjects genuinely believed they were in a situation where they were choosing between saving five from an oncoming train by killing one on another track. Given such a coincidence, it is extremely likely that this milestone was added after Munroe saw the episode. Evaluating arbitrarily complex Boolean expressions on "honk if [...]" bumper stickers and responding accordingly (title text) As with the cut-off milestone, this implies the development of artificial intelligence unrelated to the basic functions of a car, though still imitating human drivers' behavior. This joke is a reference to a previous comic about honking and formal logic . Upcoming and recently-achieved Self-driving car milestones Automatic emergency braking Highway lane-keeping Self-parking Full highway autonomy First sex in a self-driving car Full trips with no input from driver Full trips by empty cars An empty car wandering the highways for months or years until someone notices the credit card fuel charges Cars that read other cars' bumper stickers before deciding whether to cut them off Autonomous engine revving at red lights Self-loathing cars Autonomous canyon jumping Cars capable of arguing about the trolley problem on Facebook

Bad Code

Bad Code

https://www.xkcd.com/1926

https://www.explainxkcd.com/wiki/index.php/1926:_Bad_Code

[Cueball is at his desk on a swivel chair, using his computer. Ponytail walks towards him.] Ponytail: That's the ugliest mess of code I've ever seen. What on earth are you working on? [Cueball swivels his chair to face Ponytail in a frameless panel.] Cueball: It's nothing weird this time, I swear. Cueball: It just looks bad because it's a spreadsheet formula. [Cueball is turns back towards the computer while Ponytail looks over his shoulder at the computer screen.] Cueball: ...which assembles a Haskell function. Ponytail: Uhhh. Cueball: ...for parsing HTML. Ponytail: ...oh my God. [Ponytail points away from the scene while still looking at the computer screen.] Cueball: It's ok! Nothing depends on this. Ponytail: That wall isn't load-bearing. Does that mean we can just throw hammers at it? Cueball: ...I mean... Ponytail: Wait. Crap.

This comic is the fourth in the Code Quality series: Ponytail has caught Cueball in the act of writing some messy code — code in the form of a spreadsheet formula, which in turn produces another program in a language called Haskell . Haskell is a purely functional programming language, a concept that has a debatably steep learning curve, which causes it to be somewhat obscure, as referenced in 1312: Haskell . It is explained that this code will, in turn, interpret more source code, specifically code written in HTML . Parsing HTML is notoriously tricky without a dedicated software library for several reasons, including frequent changes to web pages, a nested structure of tags and quotes that frustrates regular expressions , allowing new lines to be started almost anywhere, and different standards that are followed or not followed to varying degrees. After Cueball excuses his bad code by stating that "nothing depends on this" (meaning that no other projects rely on this code being good to operate properly), Ponytail uses the analogy of breaking a non-load-bearing wall to ridicule Cueball's excuse. A load-bearing wall is a wall that plays a role in supporting the building. Damaging such a wall would threaten the structural integrity of the entire building, and could potentially cause a collapse. In contrast, walls that aren't load-bearing are designed only to separate spaces within the building, and do not contribute to keeping the building up. Damaging or destroying such walls wouldn't endanger the overall structure of the building. However, supporting the building is just one of the functions which could depend on having an intact wall, and non-load-bearing walls are still there for a purpose. Walls serve many other important purposes, from creating opaque and sound blocking barriers (desirable for privacy purposes, particularly for bedrooms and bathrooms), to containing and protecting water pipes and electrical wiring. Ponytail's analogy suggests that, even though poorly written-code wouldn't cause the entire program to fail, it's still not a good idea. Immediately after, Ponytail appears to have realized that she's only inspired Cueball to go ahead and break the wall, instead of swaying him away from writing ugly code. If left unchecked, this will only end in tragedy . This is most likely a continuation of the Code Quality series, but it differs slightly. For one thing, all of the previous strips were named "Code Quality <number>", with the exception of the first, which was just named "Code Quality". Also note that, unlike the previous Code Quality strips, Ponytail does not start using similes like "This is like being in a house built by a child using nothing but a hatchet and a picture of a house". It's also the longest explanation of Cueball's code by Cueball himself. The title text suggests that Cueball's approach to breaking the wall - scotch-taping a bunch of hammers together - is as good as his code, and his excuse is similar. [Cueball is at his desk on a swivel chair, using his computer. Ponytail walks towards him.] Ponytail: That's the ugliest mess of code I've ever seen. What on earth are you working on? [Cueball swivels his chair to face Ponytail in a frameless panel.] Cueball: It's nothing weird this time, I swear. Cueball: It just looks bad because it's a spreadsheet formula. [Cueball is turns back towards the computer while Ponytail looks over his shoulder at the computer screen.] Cueball: ...which assembles a Haskell function. Ponytail: Uhhh. Cueball: ...for parsing HTML. Ponytail: ...oh my God. [Ponytail points away from the scene while still looking at the computer screen.] Cueball: It's ok! Nothing depends on this. Ponytail: That wall isn't load-bearing. Does that mean we can just throw hammers at it? Cueball: ...I mean... Ponytail: Wait. Crap.

Tinder

Tinder

https://www.xkcd.com/1927

https://www.explainxkcd.com/wiki/index.php/1927:_Tinder

[A Smartphone is shown with the screen facing the viewer. On the screen is the Tinder UI. The main photo is of Cueball, in the cockpit of a plane which appears to be tilting to the right, holding up a makeshift sign saying:] If you know how to fly a plane please swipe right ASAP

Tinder is a social media/dating app. The main interface of Tinder shows photos of people. Users swipe right for matches that they like, and left otherwise. The purpose of the app is to get dates, with the intent of a romantic relationship or sexual intercourse. However, in the comic, Cueball is trying to use it to request assistance flying a plane instead. If the request is genuine, this is a bad situation, because it suggests Cueball is in charge of a plane he is unable to fly, and unless he finds a match with someone who can, and is able to provide assistance, the plane will crash. Even then, unless the matched person happens to be on board, and therefore able to assist directly, providing help through Tinder messages is unlikely to be a sufficiently efficient way of solving the problem. Alternatively, Cueball may simply be pretending that there is an emergency so that he can get matches on Tinder. In either case, depending on the jurisdiction, Cueball may be violating the law by using a cell phone that is not in "airplane mode" (in some phones, "flight mode" or "offline mode") when on an airplane. WiFi can be enabled on some flights during the entire flight; in others it may be banned during takeoff and landing. Even if he is either uploading the picture after the flight or using the in-flight internet service, he is still violating other, more serious laws (if he is a pilot, he may be liable for negligence, and if he is an ordinary passenger, God knows what he may have done...) The title text explains that Cueball's unwise method for getting help stems from astonishingly skewed priorities and no small amount of selfishness. He claims to strongly dislike conversing over audio-only channels, and this dislike is apparently so overwhelming that he would rather jeopardize his life and that of any passengers on the plane, than put aside his own hang-ups. Even if we give Cueball the benefit of the doubt and assume that he has a phobia of public speaking, most human beings tend to automatically suspend their irrational anxieties when experiencing the fear of imminent mortal peril, at least until after the danger has passed. For example, those normally afraid of dating Cueball would "match" with him to prevent a plane crash, which may be his secret intent after all. Randall may be satirizing people who use Tinder (and other similar social apps) by portraying an extreme caricature of a Tinder user. This comic is similar to 1897: Self Driving , and as well as 582: Brakes , which also is about bad ways to get help in emergencies and other time-critical situations. Note that the photo is at an angle, but the view out of the window shows the airplane to be in level flight. This could be due to haste taking the picture, or a feigned haste in taking the picture, or could suggest that, for whatever reason, the photo is making the situation seem worse than it is. [A Smartphone is shown with the screen facing the viewer. On the screen is the Tinder UI. The main photo is of Cueball, in the cockpit of a plane which appears to be tilting to the right, holding up a makeshift sign saying:] If you know how to fly a plane please swipe right ASAP

Seven Years

Seven Years

https://www.xkcd.com/1928

https://www.explainxkcd.com/wiki/index.php/1928:_Seven_Years

[The first eight panels, used earlier in the comic 1141: Two Years , are faded out.] [Randall and Randall's fiancée sit on a bed, Randall's fiancée is talking on the phone. The person she is talking to, a doctor holding a clipboard, is shown inset.] Randall's fiancée: Oh god. [Randall and Randall's fiancée sit together while Randall's fiancée, now bald, is receiving chemotherapy. They are both on their laptops.] IV pump: ... Beeep ... Beeep ... Beeep ... [Randall and Randall's fiancée (who is wearing a knit cap) are paddling a kayak against a scenic mountain backdrop.] [Randall and Randall's fiancée sit at a table, staring at a cell phone. There is a clock on the wall. Her head is stubbly.] Randall's fiancée: How long can it take to read a scan!? [Randall and Randall's fiancée are back at the hospital again, Randall's fiancée receiving chemo. They are playing Scrabble.] Randall: "Zarg" isn't a word. Randall's fiancée: But caaaancer. Randall: ...Ok, fine. [Randall and Randall's fiancée (wearing a knit cap) are listening to a Cueball-like friend. A large thought bubble is above their heads and it obscures the friends talk. The text below, split in three is the only part there can be no doubt about:] Friend: So next year you should come visit us up in the mounta a and Randall and Randall's fiancée (thinking): "Next year" [Randall and Randall's fiancée are getting married, with a heart above their heads. Randall's wife's hair is growing back.] [Randall and Randall's wife (wearing a knit cap) stand on a beach, watching a whale jump out of water. This is the last gray panel, with an additional label in normal black color.] Fwoosh Label: Two years [Randall and Randall's wife (with her hair noticably longer) are walking through a forest.] [Randall's wife is sitting down, not in the forest anymore.] Randall's wife: My toe hurts and I found a report of a case in which toe pain was an early sign of cancer spreading. Randall: Wait—didn’t you stub your toe yesterday? Randall's wife: Yes, but what if this is unrelated? [Randall and his wife are going spelunking. The guide is gesturing deeper into the cave while Randall and his wife are climbing down.] [Randall's wife stands on a rock above an alligator in a swamp, photographing the alligator. Randall is on a balcony behind safety railings.] Randall: When they estimated your survival odds, I think they made some optimistic assumptions about your hobbies. [Randall's wife sits on an examination bed, listening to a doctor holding a clipboard.] Doctor: This is probably nothing. Doctor: But given your history, we should do a full scan. Doctor: We'll call with the results in a few days. Try not to worry about it until then! [Randall and his wife stand above a deep pond full of fish and other objects. Randall's wife is piloting a wired underwater camera with lights.] [Randall and his wife are standing next to each other. Randall's wife has shoulder-length hair covering most of her face.] Randall's wife: Hard to believe—six years ago, I was bald. But today, after a long struggle, I finally look like the little girl from The Ring . Randall: That's, uhh... good? Randall's wife: Hissssss [A line of six people, including Randall and his wife, stand and watch the solar eclipse.] [The sky has been brightened.] Ponytail: Wow. Randall's wife: Yeah. [Randall and his wife are walking together and holding hands.] Randall's wife: That was incredible. Randall's wife: When's the next one? Randall: In seven years. Randall: Wanna go see it? [Still walking, Randall and his wife think together about a timeline. Seven years have passed since 2010, represented with a solid line from the past to 2017; seven years in the future will be 2024, represented with a dotted line into the future and surrounded by three question marks.] [The pair keeps walking.] Randall's wife: Yeah. Randall's wife: I'll do my best. Randall: It's a date!

Randall 's then girlfriend, now wife, was diagnosed with cancer in late 2010, a matter he has discussed in the comic multiple times before . Here, motivated by the seven-year period between the American solar eclipses of 2017 and 2024 , we see them reminiscing the seven years prior to the first eclipse, leaving an open question to what the next seven years will bring. This comic is part of a series of comics and directly continues 1141: Two Years , which is shown as the first eight panels, slightly grayed out. It later continued in 2386: Ten Years . It was released as a response to another cancer diagnosis, this is explained in the Header text , which, for this comic only , has replaced the standard xkcd updates every Monday, Wednesday, and Friday. The header for this comic, with the active link included, is: Becky Beaton, sister of fellow cartoonist Kate Beaton, has also been diagnosed with cancer. You can support her treatment here . Kate Beaton is the creator of the web comic Hark! A Vagrant . Although this comic is not one on Randall's list of Comics I enjoy , he is clearly much influenced by another cancer diagnosis among someone in his own creative field. Explanations of the individual panels: The title text is a continuation to panel 15 concerning the horror movie The Ring . Specifically, watching the videotape in The Ring is supposed to kill a person in seven days, but the title text instead says "seven years". With all these thoughts in mind, there is no wonder that he wishes to participate in helping a colleague's cancer-stricken sister with the unique header text above this comic, as mentioned above. [The first eight panels, used earlier in the comic 1141: Two Years , are faded out.] [Randall and Randall's fiancée sit on a bed, Randall's fiancée is talking on the phone. The person she is talking to, a doctor holding a clipboard, is shown inset.] Randall's fiancée: Oh god. [Randall and Randall's fiancée sit together while Randall's fiancée, now bald, is receiving chemotherapy. They are both on their laptops.] IV pump: ... Beeep ... Beeep ... Beeep ... [Randall and Randall's fiancée (who is wearing a knit cap) are paddling a kayak against a scenic mountain backdrop.] [Randall and Randall's fiancée sit at a table, staring at a cell phone. There is a clock on the wall. Her head is stubbly.] Randall's fiancée: How long can it take to read a scan!? [Randall and Randall's fiancée are back at the hospital again, Randall's fiancée receiving chemo. They are playing Scrabble.] Randall: "Zarg" isn't a word. Randall's fiancée: But caaaancer. Randall: ...Ok, fine. [Randall and Randall's fiancée (wearing a knit cap) are listening to a Cueball-like friend. A large thought bubble is above their heads and it obscures the friends talk. The text below, split in three is the only part there can be no doubt about:] Friend: So next year you should come visit us up in the mounta a and Randall and Randall's fiancée (thinking): "Next year" [Randall and Randall's fiancée are getting married, with a heart above their heads. Randall's wife's hair is growing back.] [Randall and Randall's wife (wearing a knit cap) stand on a beach, watching a whale jump out of water. This is the last gray panel, with an additional label in normal black color.] Fwoosh Label: Two years [Randall and Randall's wife (with her hair noticably longer) are walking through a forest.] [Randall's wife is sitting down, not in the forest anymore.] Randall's wife: My toe hurts and I found a report of a case in which toe pain was an early sign of cancer spreading. Randall: Wait—didn’t you stub your toe yesterday? Randall's wife: Yes, but what if this is unrelated? [Randall and his wife are going spelunking. The guide is gesturing deeper into the cave while Randall and his wife are climbing down.] [Randall's wife stands on a rock above an alligator in a swamp, photographing the alligator. Randall is on a balcony behind safety railings.] Randall: When they estimated your survival odds, I think they made some optimistic assumptions about your hobbies. [Randall's wife sits on an examination bed, listening to a doctor holding a clipboard.] Doctor: This is probably nothing. Doctor: But given your history, we should do a full scan. Doctor: We'll call with the results in a few days. Try not to worry about it until then! [Randall and his wife stand above a deep pond full of fish and other objects. Randall's wife is piloting a wired underwater camera with lights.] [Randall and his wife are standing next to each other. Randall's wife has shoulder-length hair covering most of her face.] Randall's wife: Hard to believe—six years ago, I was bald. But today, after a long struggle, I finally look like the little girl from The Ring . Randall: That's, uhh... good? Randall's wife: Hissssss [A line of six people, including Randall and his wife, stand and watch the solar eclipse.] [The sky has been brightened.] Ponytail: Wow. Randall's wife: Yeah. [Randall and his wife are walking together and holding hands.] Randall's wife: That was incredible. Randall's wife: When's the next one? Randall: In seven years. Randall: Wanna go see it? [Still walking, Randall and his wife think together about a timeline. Seven years have passed since 2010, represented with a solid line from the past to 2017; seven years in the future will be 2024, represented with a dotted line into the future and surrounded by three question marks.] [The pair keeps walking.] Randall's wife: Yeah. Randall's wife: I'll do my best. Randall: It's a date!

Argument Timing

Argument Timing

https://www.xkcd.com/1929

https://www.explainxkcd.com/wiki/index.php/1929:_Argument_Timing

[Shown is a curved time plot. There is a black line, marked "Before Smartphones and Facebook" and a red line marked "After." On the y-axis the label reads "Odds of getting in a friendship-ending argument." while there is no scale shown. On the x-axis, at uneven intervals some times of the day are marked as "Wake up", "Get out of bed", "Breakfast", "Lunch", "Dinner", "Go to bed", and "Fall asleep."] [With the exception of "Waking up" and "Falling asleep", the red line is slightly lower than the black line. Directly after "Waking up" and during the interval between "Going to bed" and "Falling asleep", the black line is near zero while the red line peaks.]

This comic comments on how (a) the prevalence of using mobile devices in bed, combined with (b) burgeoning use of social media, especially Facebook , has increased the potential for conflict by encouraging early morning and late night communications, when those involved may not be at their most clear-headed. Before mobile devices were common, the ability to argue on-line usually ended when a person left their computer to go to bed. Before social media was common, arguments with friends would mostly occur in person or during a phone call. The 'old-fashioned' cycle for arguing suggests that the odds start at near zero, because most people didn't interact with others immediately after waking up unless they lived together, and even then were unlikely to get in arguments first thing in the morning. The frequency increased as the day went on, with peaks at breakfast, lunch and dinner, and a final peak in the evening. This likely indicates that people would frequently share meals with friends and loved ones, then spend time together in the evenings, meaning those times had the most potential for conflict. As the evening ended, the odds fell away dramatically, becoming very low by bedtime, and effectively zero immediately afterward. The red line, indicating argument frequency with mobile devices and social media, has a similar trend, but is distorted by massive peaks between waking up and getting out of bed, and then between going to bed and going to sleep. This suggests that, in Munroe's experience, most relationship-ending arguments in modern times happen over social media and electronic communication, while still in bed. It's not clear whether this indicates people primarily using their devices in bed, or just that people tend to get into arguments more while posting in bed (possibly making less inhibited and diplomatic comments due to fatigue). It could also be that people objecting to their partners using social media in bed is also contributing to the number of arguments. Interestingly, this line indicates the chances of conflict in the mobile/Facebook era remains above zero for a short time after one goes to sleep. This may suggest that Randall sometimes falls asleep while writing a social media post but finishes it while sleep-typing, or it may be that he is prone to sending out ill-considered messages just before going to sleep, which are only later picked up, unwelcomed, by the recipient. The title text talks about different types of arguers, saying that some people argue more at certain times, or in certain states. "Hangry" is a portmanteau of "hungry" and "angry", meaning bad-tempered or irritable as a result of hunger. 490: Morning Routine covers similar ground to this comic. [Shown is a curved time plot. There is a black line, marked "Before Smartphones and Facebook" and a red line marked "After." On the y-axis the label reads "Odds of getting in a friendship-ending argument." while there is no scale shown. On the x-axis, at uneven intervals some times of the day are marked as "Wake up", "Get out of bed", "Breakfast", "Lunch", "Dinner", "Go to bed", and "Fall asleep."] [With the exception of "Waking up" and "Falling asleep", the red line is slightly lower than the black line. Directly after "Waking up" and during the interval between "Going to bed" and "Falling asleep", the black line is near zero while the red line peaks.]

Calendar Facts

Calendar Facts

https://www.xkcd.com/1930

https://www.explainxkcd.com/wiki/index.php/1930:_Calendar_Facts

-Calendar Facts- [Shown below is a branching flow chart of sorts that begins at the phrase "Did you know that", then flows through various paths to build up a sentence. (Note that the "→" arrow symbol is used below to indicate a new branch with no intermediate text from a previous branch.)] Did you know that: the ( Fall | Spring ) Equinox the ( Winter | Summer ) ( Solstice | Olympics ) the ( Earliest | Latest ) ( Sunrise | Sunset ) Daylight ( Saving | Savings ) Time Leap ( Day | Year ) Easter the ( Harvest | Super | Blood ) Moon Toyota Truck Month Shark Week → happens ( earlier | later | at the wrong time ) every year drifts out of sync with the Sun Moon Zodiac ( Gregorian | Mayan | Lunar | iPhone ) Calendar atomic clock in Colorado might ( not happen | happen twice ) this year because of time zone legislation in ( Indiana | Arizona | Russia ) a decree by the pope in the 1500s ( precession | libration | nutation | libation | eccentricity | obliquity ) of the Moon Sun Earth's axis equator prime meridian ( International Date | Mason-Dixon ) Line magnetic field reversal an arbitrary decision by ( Benjamin Franklin | Isaac Newton | FDR ) ? Apparently it causes a predictable increase in car accidents. that's why we have leap seconds. scientists are really worried. it was even more extreme during the Bronze Age. Ice Age. Cretaceous. 1990s. there's a proposal to fix it, but it will never happen. actually makes things worse. is stalled in congress. might be unconstitutional. it's getting worse and no one knows why.

This is the second comic using Facts in the title. Randall presents what appears to be a generator of 156,000 facts [20 x 13 x (8 + 6 x 7) x 12], about calendars, most of which are false or have little meaning [ citation needed ] . The facts are seeded by a mishmash of common tidbits about the time of year. The formula for each generated fact goes as follows: "Did you know that [a recurring event] [occurs in an unusual manner] because of [phenomena or political decisions] ? Apparently [wild card statement] ." This is the fifth time that Randall has referred to the phenomenon of a supermoon , which he typically makes fun of, most prominently in 1394: Superm*n . The title text continues the chart with supposed real-life consequences of the trivia in the comic. There are multiple online generators of Calendar 'facts' using this formula here and here . All 156 000 possible combinations can be found here , lovingly assembled by hand (or rather, by a python script) for your entertainment. A random fact generator (including title text), written in Python, can be found here . -Calendar Facts- [Shown below is a branching flow chart of sorts that begins at the phrase "Did you know that", then flows through various paths to build up a sentence. (Note that the "→" arrow symbol is used below to indicate a new branch with no intermediate text from a previous branch.)] Did you know that: the ( Fall | Spring ) Equinox the ( Winter | Summer ) ( Solstice | Olympics ) the ( Earliest | Latest ) ( Sunrise | Sunset ) Daylight ( Saving | Savings ) Time Leap ( Day | Year ) Easter the ( Harvest | Super | Blood ) Moon Toyota Truck Month Shark Week → happens ( earlier | later | at the wrong time ) every year drifts out of sync with the Sun Moon Zodiac ( Gregorian | Mayan | Lunar | iPhone ) Calendar atomic clock in Colorado might ( not happen | happen twice ) this year because of time zone legislation in ( Indiana | Arizona | Russia ) a decree by the pope in the 1500s ( precession | libration | nutation | libation | eccentricity | obliquity ) of the Moon Sun Earth's axis equator prime meridian ( International Date | Mason-Dixon ) Line magnetic field reversal an arbitrary decision by ( Benjamin Franklin | Isaac Newton | FDR ) ? Apparently it causes a predictable increase in car accidents. that's why we have leap seconds. scientists are really worried. it was even more extreme during the Bronze Age. Ice Age. Cretaceous. 1990s. there's a proposal to fix it, but it will never happen. actually makes things worse. is stalled in congress. might be unconstitutional. it's getting worse and no one knows why.

Virtual Assistant

Virtual Assistant

https://www.xkcd.com/1931

https://www.explainxkcd.com/wiki/index.php/1931:_Virtual_Assistant

[Megan stands next to a small table with a Google Home sitting on it.] Megan: Ok, Google– Google Home: THUMP-THUMP-THUMP Google Home: CRASH  THUD! Google Home: CLICK  THUMP THUMP Google Home: [sink running] Google Home: ZIIIIIP!  CLICK Google Home: THUMP THUMP  CLICK Google Home: SLAM! Google Home: THUMPATHUMPATHUMPA Google Home: H... *Pant* ...Hello... *Pant* Google Home: How... How can I help you? [Text below the panel:] I want to hack the world's smart home devices, but not to create a botnet or anything—I just want to make them play this sound clip every time you invoke them.

Megan invokes her smart device's virtual assistant with the keyphrase "Okay Google", intending to follow up with a voice command (e.g. "Check the weather forecast" or "Order two tons of creamed corn" ). But before she can continue, the smart device interrupts her with a comical cacophony of assorted noises, as a supposed assistant living in the device clumsily rushes from a distant room to Megan's location. The sounds can be interpreted as: tromping down stairwells, knocking over a fragile antique, opening a locked door, taking a quick pit stop in the bathroom, going back through the door, running across another hardwood floor, opening and slamming another door, and finally running up to Megan, greeting her while clearly being out of breath. The idea of a product that is (in reality) a virtual assistant [ citation needed ] being an actual person with physical form was featured a few days before this comic on Live from Here on December 16, 2017, in a segment in which Amazon.com and its virtual assistant Alexa were satirized as "Amazon Lazy", which delivered the user things that were already in the user's home -- or simply carried the user from one room of the house to another. (Audio available at https://www.livefromhere.org/shows/59375 ) Randall is amused by the idea that such a "virtual" assistant made "real" might be rather clumsy. In fact, Randall finds the concept so humorous that he would like to troll smart device owners by hacking and re-programming their devices to play this sound file whenever the VA is invoked. He makes it clear that he doesn't want to create a botnet with them, perhaps in reference to the infamous Mirai attacks of 2016, whose creators pled guilty in court a week before the comic was posted. Another similar activity that is gaining popularity is hacking IP webcams with embedded speakers for comedic purposes (here's a YouTube channel ). The title text extends the concept further. If the owner attempts to disable the feature, rather than refrain from playing the clip, the virtual assistant apologetically promises to be quieter next time; thereafter, the device plays a modified version of the clip where the noises are only slightly diminished and punctuated with additional apologies from the live-in assistant. Randall has characterized the assistant as being incapable of answering without causing a ruckus. A previous comic, 1897: Self Driving , also toys with the idea that AI is actually just people behind-the-scenes. Sounds of things falling over and breaking off-screen is a comedic trope used in movies. The idea of making it look as if excessive work is put in to being ready to answer the user may be a reference to the Monty Python "it's" man. [Megan stands next to a small table with a Google Home sitting on it.] Megan: Ok, Google– Google Home: THUMP-THUMP-THUMP Google Home: CRASH  THUD! Google Home: CLICK  THUMP THUMP Google Home: [sink running] Google Home: ZIIIIIP!  CLICK Google Home: THUMP THUMP  CLICK Google Home: SLAM! Google Home: THUMPATHUMPATHUMPA Google Home: H... *Pant* ...Hello... *Pant* Google Home: How... How can I help you? [Text below the panel:] I want to hack the world's smart home devices, but not to create a botnet or anything—I just want to make them play this sound clip every time you invoke them.

The True Meaning of Christmas

The True Meaning of Christmas

https://www.xkcd.com/1932

https://www.explainxkcd.com/wiki/index.php/1932:_The_True_Meaning_of_Christmas

[Cueball is talking to a guy wearing a Santa hat.] Cueball: You’re looking festive. Santa Hat: I love Christmas! Cueball: Really? Doesn’t seem like your kind of thing. Santa Hat: It’s our most meta holiday! [Same setting.] Cueball: How so? Santa Hat: All our Christmas stories now are about discovering the “true meaning of Christmas.” [The same setting in a frame-less panel where Santa Hat shrugs.] Cueball: Huh, yeah. And then sharing it with others. Santa Hat: At some point, that quest itself became the true meaning. [Same setting with Santa Hat holding a hand to his chin.] Cueball: Like a word whose definition is “the act of looking up the definition of this word.” Santa Hat: “Autometalogolex”? Cueball: My least favorite of Santa’s reindeer.

This is the first of two Christmas comics in a row. It is making fun of the common trope in popular media that the true meaning of Christmas is about family, friends, and sharing the Christmas Spirit. It subverts the trope by suggesting that once the stories of the "True Meaning of Christmas" become sufficiently common, the real true meaning becomes to spread those stories. Thus the search for the "True Meaning of Christmas" is itself the meaning of Christmas, in a sort of "the journey is the reward" discovery. In the last panel and title text, "Autometalogolex" is a neologism of Randall's, which can be broken down to its various prefixes and the root: "Auto-" - Greek meaning "self." "Meta-" - Greek meaning "after," "beyond," or "in reference to." "Logo-" - Greek meaning "word" or "speech." "Lex" - "lexis" is another Greek word meaning "word"; but in this case it is more likely to be a shortening of "lexicon" (another word for dictionary), or perhaps a reference to the process of "lexing" (lexical analysis), part of the process of computer analysis of text. Thus, "Autometalogolex" would literally mean "A word that refers to itself in the dictionary," or more precisely "the act of looking up the definition of autometalogolex", which leads to a recursion, as all meaning of Christmas stories do. Recursion and self-reference is a recurring theme in xkcd. The term Autometalogolex might also refer to autological words, words that refer to a property of the word itself. ("noun" is a noun, "pentasyllabic" is pentasyllabic [has 5 syllables]). "Autometalogolex" is a 'meta' version of the looking up (lex) of an autological word. Cueball finally states that Autometalogolex is his least favorite of Santa Claus's reindeer . This is not among the commonly quoted list of names: Dasher , Dancer , Prancer , Vixen , Comet , Cupid , Donder , and Blitzen . [ citation needed ] As the title text reveals this ninth reindeer could be a reference to Rudolph the Red-Nosed Reindeer , who was not accepted by the others until Santa had problems and asked it to lead the other reindeer pulling the sleigh. The title text may also imply the only effective outcome of Autometalogolex (or the newly defined Christmas) is giving headaches, as with many self-referential concepts. As headaches generally are bad, Autometalogolex is not accepted, but - as in a typical Christmas story, here driven into the absurd realm - Santa needed a headache, and Autometalogolex was there to save the day. [Cueball is talking to a guy wearing a Santa hat.] Cueball: You’re looking festive. Santa Hat: I love Christmas! Cueball: Really? Doesn’t seem like your kind of thing. Santa Hat: It’s our most meta holiday! [Same setting.] Cueball: How so? Santa Hat: All our Christmas stories now are about discovering the “true meaning of Christmas.” [The same setting in a frame-less panel where Santa Hat shrugs.] Cueball: Huh, yeah. And then sharing it with others. Santa Hat: At some point, that quest itself became the true meaning. [Same setting with Santa Hat holding a hand to his chin.] Cueball: Like a word whose definition is “the act of looking up the definition of this word.” Santa Hat: “Autometalogolex”? Cueball: My least favorite of Santa’s reindeer.

Santa Facts

Santa Facts

https://www.xkcd.com/1933

https://www.explainxkcd.com/wiki/index.php/1933:_Santa_Facts

[An annotated picture of Santa is shown.] Santa Facts and Figures Type: Flying/Psychic Plural: "Santa" Active Warrants: 5 Lubricated for easy passage down chimneys Vertical leap: 14 Miles Sleigh flag of convenience: Panama 9th in presidential line of succession Not technically an insect—actually an arthropod Only known vampire able to enter house without being invited Works with Alexa Ribbed IUCN red list: Critically endangered Diet: 80% Reindeer Liability Insurance: None

This, the second Christmas comic in a row, provides some dubious "Facts" and "Figures" of the creature known as "Santa". We can see from the drawing that this is obviously meant to be either Santa Claus or a parody of Santa Claus. It is the third comic using Facts in the title. This comic is reminiscent of the xkcd Phones series . Type: Flying/Psychic A reference to Pokémon . The type of a Pokémon describes and determines its abilities (including attacks), affinities, and general nature. In most stories Santa Claus rides a sled pulled by flying reindeer (all other Flying-type Pokémon fly under their own power) and some kind of magical power. Psychic possibly refers to his ability to know a child's activities and behavior, including when they are sleeping or awake , implying a psychic ability to read minds. There is a Pokémon based on Santa, Delibird , although it is Ice/Flying instead of Flying/Psychic. Plural: "Santa" The plural form of 'Santa' conveniently parallels that of 'reindeer' (as well as those of all species of Pokémon and the term "Pokémon" itself). In real life, "santa" means "saint" in most Romance languages . However "santa" is not plural in any of these languages (for example, in Portuguese the proper plural would be "santos"). Under the most common English approach for making a plural noun, Santa would have a plural of "Santas". Taking "Santa Claus" as a separate noun, the plural would be "Santa Clauses". Active warrants: 5 There is an active warrant for Santa's arrest in 5 jurisdictions, presumably for breaking and entering or for operating a flying sleigh without the proper licensing, while drunk, or over the speed limit. Lubricated for easy passage down chimneys The diagram indicates that Santa's attire is lubricated to ease his traditional method of ingress and egress. This explanation is incomplete, however, as a great many chimneys have cross-sectional area substantially smaller than that of a normal human body, let alone a portly one, as commonly described. The common presence of chimney caps, fireplace dampers, and the like would also impede Santa's passage down a great many chimneys. That said, if we take the classic poem " A Visit from St. Nicholas " into account, the statement is technically true, just "lubricated" with magic rather than physical lubrication. A less classic example of Santa going down the chimney with help of magic can be seen in The Santa Clause [1] . "Lubricated" is also a reference to lubricated condoms - see "Ribbed" below. Vertical Leap: 14 Miles For a non-magical being or object, a vertical leap of 14 miles (~23 km), ignoring air resistance would require an initial launch velocity of slightly more than 2180 feet per second (665 m/s), somewhat over twice the speed of sound. Achieving this velocity by means of bending then straightening the legs would require an acceleration of roughly 25,000 G, placing extraordinarily high demands on the strength of the legs. As Santa does not have a particularly aerodynamic shape, air resistance would increase the launch velocity and launch acceleration requirements substantially. Santa may be able to overcome these problems due to his magical nature; however, there is clearly still a limit to what this can achieve, as there is a maximum to his leaping ability. Sleigh Flag of Convenience: Panama The Flag of Convenience identifies the country in which an ocean-going vessel has its registration information. Panama maintains one of the top three open registries. Owners of a vessel may choose to use an open registry to avoid labor or safety regulations of the owner's country. They may also choose such a registry to help obscure ownership of the vessel. Which concern applies in the case of Santa's sleigh is not stated, or (more likely) not known. It may also be the only type of registration available, since the north pole is not in any country, so there is no "owner's country". However, a ship's flag state exercises regulatory control over the vessel and is required to inspect it regularly, certify the ship's equipment and crew, and issue safety and pollution prevention documents. One suspects that this does not , in fact, happen regularly with Santa's sleigh. Also, as a flying sleigh, the registry for ocean-going vessels is not applicable. Instead, it would be registered as an aircraft, with the FAA (in the U.S.), EASA (in Europe), or the equivalent in another country. Civilian aircraft have their registration number painted on their tails, but are not required to display a "flag". (However, U.S. Airways used a stylized version of a U.S. flag as a corporate logo prior to its merger with American Airlines.) The country being Panama may be a reference to the Panama Papers 9th in Presidential Line of Succession The Presidential Line of Succession specifies the order in which persons may become or act as President of the United States if the incumbent President becomes incapacitated, dies, resigns, or is removed from office. Having Santa as the 9th in that order would place him above the Secretary of Agriculture . An alternative interpretation would hold that Santa is the present Secretary of Agriculture, Tom Vilsack . Assuming Tom Vilsack is not Santa Claus, Santa is likely ineligible for the Presidency, as most origin stories of Santa have him a natural-born citizen of a European country (or of Turkey) rather than the United States. Alternately, Santa might be old enough to qualify under the "citizen at the time of the adoption of this constitution" clause, although in light of the information that Santa is actually an arthropod and/or a vampire (see below), his status as an American citizen is dubious. Not technically an insect — actually an arthropod This "fact" uses an absurd misconception to correct a relatively common misconception. Absurdly, Randall has mistaken Santa for a lobster, given his bright red coloration and the surname Claus (which is pronounced the same as a lobster's "claws"). This may be an homage to the film the Nightmare Before Christmas, where Jack Skellington believes Christmas Town is led by "Sandy Claws" who is "like a lobster, huge and red". There is a relatively common misconception that lobsters are insects. In fact, lobsters are crustaceans, but there is a kernel of truth to the misconception, as crustaceans and insects are related (both are arthropods). Thus, the "fact" states that Lobster-Santa is not technically an insect; he is actually an arthropod. Only known vampire able to enter house without being invited In traditional vampire folklore, a vampire cannot enter an abode without an invitation from the owner of the same . Santa, however, seems to be able to enter houses even without explicit invitation (although plenty of children do welcome him, either via written notes or by their general sentiments), so if he is a vampire he is the exception to that rule. This juxtaposes interestingly with the previous point about his arthropod nature. His being a vampire is perhaps related to his dressing all in red, and alleged immortality. Works with Alexa May have any of several meanings, including that Alexa (Amazon's virtual assistant) is Santa's colleague, that Santa uses Alexa in his work, that Santa is somehow functionally compatible with Alexa, or a reference to various Santa-themed 'skills' that Alexa can be associated with. A common advertisement states that a product is compatible with Amazon's smart device, Alexa. But it could also be a play on the idea or fear that Alexa may be used to spy on people from the privacy of their own homes, much like what is claimed of Santa ("he sees you when you're sleeping, [...]"). Finally, several skills designed to entertain users of Alexa are themed around Santa Claus, including asking Alexa where Santa is on Christmas Eve, whether or not you've been naughty or nice, or even leaving the jolly old elf a voicemail. Ribbed A reference to condoms, which have ridges or ribbing in order to promote pleasurable stimulation during coitus (see "Lubricated" above). This also puns on the fact that, as a humanoid, Santa presumably has a rib cage. (This might directly contradict the claims about his being an arthropod.) IUCN Red List: Critically endangered The International Union for Conservation of Nature (IUCN) monitors the size and viability of populations of organisms; 'critically endangered' marks a population as being highly susceptible to extinction. Santa, being one (or possibly two, if we include his wife) of a kind and lacking any offspring (and, indeed, likely being incapable of effectively producing any), will most likely be the last member of his population; thus extinction will arrive with his or his wife's death. Note, however, that the presence on the Red List implies that "Santa" is a biological species, not a fantasy, robot, or other non-biological entity. This is consistent with Santa being an arthropod and/or vampire, but would suggest that there are many specimens of Santa, while other 'Facts' (such as having a definite ranking in the Presidential Line of Succession) suggest Santa to be a single individual. Diet: 80% Reindeer A mocking allusion to Santa Claus's sleigh, usually pulled by reindeer. Usual folklore depict Santa Claus being extremely fond of his reindeer, thus making it a humorous contrast to suggest he'd be eating reindeer meat on a daily basis. Liability Insurance: None As a result of his diet (see above), alleged criminal activity (ditto), species ambiguity, and occupation, Santa would find the cost of liability insurance quite high. He instead chooses to 'go bare' and operate without any. The title text states that as a result of intervention Santa's diet is now 20% milk & cookies, implying that previously it was 100% Reindeer. It is a tradition to leave out milk and cookies as a "gift" for Santa. If he is indeed a vampire, it is odd that Santa could survive on a diet of reindeer, milk, and cookies, since vampires supposedly need human blood to survive. Of course, his entering without being invited already shows Santa to be a highly unusual vampire. Additionally, it is possible that he consumes reindeer blood as part of his reindeer diet (vampires living off animal blood is not unheard of in modern fantasy). Related to that may be the observation that he seems to develop "nutritional deficiencies" when going below 80% reindeer meat, as that would logically result in him consuming less blood and thus starvation due to his vampiric nature. [An annotated picture of Santa is shown.] Santa Facts and Figures Type: Flying/Psychic Plural: "Santa" Active Warrants: 5 Lubricated for easy passage down chimneys Vertical leap: 14 Miles Sleigh flag of convenience: Panama 9th in presidential line of succession Not technically an insect—actually an arthropod Only known vampire able to enter house without being invited Works with Alexa Ribbed IUCN red list: Critically endangered Diet: 80% Reindeer Liability Insurance: None

Phone Security

Phone Security

https://www.xkcd.com/1934

https://www.explainxkcd.com/wiki/index.php/1934:_Phone_Security

[The content of a configuration screen on a smartphone is shown. All items listed are activated as indicated by green switches.] Security Options Passcode to unlock (Set Code) Erase phone after ten failed unlock attempts If stolen, phone can be remotely Tracked Erased Detonated If phone is stolen, erase data and play an earsplitting siren until the battery dies or is removed If phone is stolen, do a fake factory reset. Then, in the background... ...constantly request dozens of simultaneous rideshares to the phone's location ...automatically order food to phone's location from every delivery place within 20 miles ...if thief logs in to Facebook, send hostile messages to all their family members ...automatically direct self-driving car to drive toward phone's location at 5 mph ...take photos of random objects at the thief's address and post them as "free" on Craigslist and Nextdoor

This comic pokes fun at various phone security measures. At first, it covers some real measures, and then continues on to measures that are clearly somewhat overzealous or otherwise humorous. It is worth noting that all of the options are turned ON in the screen shown, so apparently the owner must be very afraid that their phone is going to be stolen, or just wants to see what will happen. These may be options that would appear on the xkcd Phone , but that is not mentioned specifically, and this comic does not appear to be directly linked. The first two options: Set Passcode to Unlock , and Erase phone after 10 failed unlock attempts are both real security measures found on many phones. The remaining options would rely on the fact that the phone could sense that it is stolen: If stolen, phone can be remotely... The items on this sub-heading indicate the requirements of a separate device (i.e. the owner's laptop). The phrasing leaves it ambiguous whether they are only available when it is sensed to be stolen, or if they are simply indicators of whether the owner can perform the given actions when activated. If the phone is stolen, play an earsplitting siren until the battery dies or is removed : This would be to draw attention to the thief, and discourage them from stealing future phones. Noticeably, it does not specify how the phone determines it is stolen, and, similar to the "detonate" option above, this has the potential to be an irritation if it is activated by accident, glitch, or hack. If the phone is stolen, do a fake factory reset. Then, in the background... : This series of options is all humorous, indicating that the phone would allow the thief to think that it had factory reset, but the phone would, in fact, not do so, and would instead annoy the thief by doing various horrible things to them. The title text extends the last category with: ...wait until they type in payment information, then use it to order yourself a new phone. If the thief used the thief's own payment information, then this would be the ultimate in poetic justice, as it would basically say that the user does not care if their phone gets stolen, because the thief will end up unintentionally buying them a new one. If the thief were to complain about this, they would have to admit that they had stolen the first phone in order to do so, which they would be disinclined to do. However, if the thief used fraudulent or stolen payment information (whether stolen by the same thief or acquired online), then the replacement phone would be purchased with the payment information of the other victim, and when that person complained, the owner of the stolen phone would appear to be the person who stole the payment information, and might be arrested for that theft. This is a very, very bad idea [ citation needed ] . Note that all of these security measures, with the possible exception of the remote detonation, could theoretically be done by a security app on a typical smartphone, although the fake factory reset and most (if not all) of what follows would likely require a phone to be rooted and have a custom operating system installed. With the advent of open source phones such as the Librem 5, tricks such as these have become much easier for the average programmer to implement, and some may already exist in the wild. (Even the remote detonation might be possible on some phones that prevent battery explosions with software rather than physical circuitry.) [The content of a configuration screen on a smartphone is shown. All items listed are activated as indicated by green switches.] Security Options Passcode to unlock (Set Code) Erase phone after ten failed unlock attempts If stolen, phone can be remotely Tracked Erased Detonated If phone is stolen, erase data and play an earsplitting siren until the battery dies or is removed If phone is stolen, do a fake factory reset. Then, in the background... ...constantly request dozens of simultaneous rideshares to the phone's location ...automatically order food to phone's location from every delivery place within 20 miles ...if thief logs in to Facebook, send hostile messages to all their family members ...automatically direct self-driving car to drive toward phone's location at 5 mph ...take photos of random objects at the thief's address and post them as "free" on Craigslist and Nextdoor

2018

2018

https://www.xkcd.com/1935

https://www.explainxkcd.com/wiki/index.php/1935:_2018

[Megan is walking.] Megan: I wonder if 2018 will be a leap year. [Now it turns out that Cueball walks behind Megan.] Cueball: ...it won't be, right? Megan: I doubt anyone knows at this point. [Same scene in a frame-less panel.] Cueball: No, it's definitely not. Leap years are divisible by 4. Megan: Right, and for odd numbers, that's easy. Megan: But 2018 is even. Megan: 50/50 chance. [Zoomed-out view with both walking in silhouette on a dark slightly curved ground.] Cueball: I can settle this with a calculator. Megan: No way. If it were easy to factor large numbers like that, modern cryptography would collapse. Cueball: I see. Megan: I just hope we manage to brute-force it by February.

In this, the first of two New Year comics in a row, Megan wonders whether 2018 will be a leap year . Cueball thinks 2018 will not be a leap year, and Megan responds that she "doubts anyone knows at this point." This appears to be a jab at people who suggest that anything they don't know is generally unknown. As Cueball says, leap years occur every four years (though there are a few exceptions - a year divisible by 100 is not a leap year, unless it is also divisible by 400), adding an extra day to account for the fact that Earth takes a bit longer than 365 days to orbit the Sun. Therefore, most years that are a multiple of four are leap years. As Megan says, this is easy for odd-numbered years, since no odd numbers are divisible by four. However, for even-numbered years, it isn't quite as simple. (Though, since the number 2,000 is evenly divisible by 4, the problem can be reduced to the much simpler question of whether the number 18 is divisible by 4.) The last panel expresses a misunderstanding of modern public-key cryptography , which relies on the fact that it is difficult to factorize large numbers. Megan is applying this concept to the year, claiming that it is hard to determine whether or not 2,018 is a multiple of four and hence is a leap year. In reality, factorization is not needed here, since we already know the factor in question, which is four. Megan states that, if it were possible to factor large numbers with a calculator, modern cryptography would collapse. While true, it is true only for truly large numbers (hundreds of digits), and no factorization is needed in this case. At the end of the strip, Megan hopes the answer can be brute-forced by February. Brute force is a method of breaking cryptography by trying every possible option until one works. This is misdirection upon misdirection, in that, even if we needed to factorize 2,018 (which we don't), the simplest brute-forcing algorithm would need to try only 14 numbers -- each prime from 2 to 43 (the square root of 2,018 is closest to 44). In cryptography, the algorithms use numbers much, much bigger than 2,018 -- on the order of hundreds or even thousands of digits. The title text refers to calculating which day Christmas will fall on. As Christmas always lands on December 25 by definition, the day of the week varies from year to year, though it's always the 359th or, in leap years, the 360th day of the year. Still, determining which day of the week December 25 lands on is not a difficult problem to solve, requiring only a few mathematical operations to compute. Alternatively, this might be an oblique reference to Easter, the date of which jumps from year to year according to a multi-layered algorithm that most people don't know. The changing date of Easter was recently included in 1930: Calendar Facts . Additionally, uncertainty with the regard to the date of Christmas has also been referenced in 679: Christmas Plans . A handy coincidence to help with this problem for those living in America or following American politics is that leap years fall on presidential election years. [Megan is walking.] Megan: I wonder if 2018 will be a leap year. [Now it turns out that Cueball walks behind Megan.] Cueball: ...it won't be, right? Megan: I doubt anyone knows at this point. [Same scene in a frame-less panel.] Cueball: No, it's definitely not. Leap years are divisible by 4. Megan: Right, and for odd numbers, that's easy. Megan: But 2018 is even. Megan: 50/50 chance. [Zoomed-out view with both walking in silhouette on a dark slightly curved ground.] Cueball: I can settle this with a calculator. Megan: No way. If it were easy to factor large numbers like that, modern cryptography would collapse. Cueball: I see. Megan: I just hope we manage to brute-force it by February.

Desert Golfing

Desert Golfing

https://www.xkcd.com/1936

https://www.explainxkcd.com/wiki/index.php/1936:_Desert_Golfing

[An analog clock showing 11:12 hangs on the wall left above of Cueball who is sitting on a couch leaning on the left armrest, feet up on the couch. He holds a smartphone horizontally and the screen is clearly brown. Above him is a large brown bubble showing the content of the screen, thus showing that he is playing Desert Golfing. The sky is light brown, the sand below is dark brown, the golf ball is white and is followed by a white line showing its trajectory towards the gray flag stick with a yellow flag on it, which is to the right of the screen. The hole is just before the flag stick, an indentation in the sand.] [The clock is now showing 12:00 and Cueball is sitting straight upright on the couch, the screen display above him shows that he continues to play, but now on a new golf hole with different contours. The trajectory of the ball is much more complicated than before, and it seems he has had to play a very special loop shot to get out of a deep pit.] [The clock is showing 12:34 as Cueball once again sits as in the first panel, but now towards the right armrest and he is almost lying down with his head on the rest. Once again the screen is visible above him and it is shown that the hole has changed again.] [The clock is showing 1:47 when Cueball, now sitting up against the right armrest, finally speaks while continuing to play, with the brown screen visible, as he holds it on his knees, but the screen display is not shown. An off-panel voice answers him from the right.] Cueball: Technically, I've been playing Desert Golfing nonstop since late 2017. Off-panel voice: Might want to take a break sometime in 2018. Cueball: Yeah, my New Year's resolution is to go to bed.

A common joke surrounding the turn of the New Year is to make a comment about "next year" on New Year's Eve or "last year" on New Year's Day. While technically correct, some people may derive a snarky humor from making observations about the span of years when the reality has been more along a span of days or even, as in this comic, only a few hours. In this, the second of two New Year comics in a row, with this one being released on New Year's Day 2018, Cueball observes that he has technically "been playing Desert Golfing nonstop since late 2017". Desert Golfing is a game that takes place in an endless side-scrolling desert, where the player can shoot a golf ball using a one finger swipe to determine direction and power. The entirety of the "golf course" is made of sand, making the physics of the golf ball more difficult to predict and control, as if from a bunker. After reaching a hole, the game automatically generates a completely random new course, making the game go on forever, and the score is purely dependent on how long you play the game. Although Cueball's statement could be taken to mean he has devoted his waking hours to the game, the clock on the wall reveals both the truth of his comment and that he is not exaggerating. While he has only been playing the game for two and a half hours, give or take, those two-and-a-half hours started at about 11:10 PM on December 31st, meaning that it is presently January 1st and he has indeed been playing the game "nonstop since late 2017" (assuming he has not taken a break to eat or use the facilities). Someone off-panel acknowledges the joke by saying that he should "take a break in 2018", and Cueball declares it is his New Year's resolution to go to bed. This is not a typical New Year's resolution, as most resolutions are about something you need to change in your life from last year, and going to bed (or at least sleeping) is not something you would have been able to avoid for a whole year. [ citation needed ] This may also be making a joke about how quickly many New Year's resolutions are broken, as Cueball has singularly failed to stick to his. New Year's resolutions have been mentioned before, the first time in 1154: Resolution , where the tradition of New Year's resolutions is the entire joke. The title text states that the only reason Cueball has stayed up to play Desert Golfing is to watch the ball drop into hole number 2018 — this is a pun on the Times Square Ball , a pyrotechnical device in New York City that lights up spectacularly as soon as the new year begins. Because the event is televised on many news channels, "watching The Ball drop" is now a common way to count down the seconds to the new year. Cueball takes this literally, and tries to drop his (golf) ball to signify the beginning of 2018. [An analog clock showing 11:12 hangs on the wall left above of Cueball who is sitting on a couch leaning on the left armrest, feet up on the couch. He holds a smartphone horizontally and the screen is clearly brown. Above him is a large brown bubble showing the content of the screen, thus showing that he is playing Desert Golfing. The sky is light brown, the sand below is dark brown, the golf ball is white and is followed by a white line showing its trajectory towards the gray flag stick with a yellow flag on it, which is to the right of the screen. The hole is just before the flag stick, an indentation in the sand.] [The clock is now showing 12:00 and Cueball is sitting straight upright on the couch, the screen display above him shows that he continues to play, but now on a new golf hole with different contours. The trajectory of the ball is much more complicated than before, and it seems he has had to play a very special loop shot to get out of a deep pit.] [The clock is showing 12:34 as Cueball once again sits as in the first panel, but now towards the right armrest and he is almost lying down with his head on the rest. Once again the screen is visible above him and it is shown that the hole has changed again.] [The clock is showing 1:47 when Cueball, now sitting up against the right armrest, finally speaks while continuing to play, with the brown screen visible, as he holds it on his knees, but the screen display is not shown. An off-panel voice answers him from the right.] Cueball: Technically, I've been playing Desert Golfing nonstop since late 2017. Off-panel voice: Might want to take a break sometime in 2018. Cueball: Yeah, my New Year's resolution is to go to bed.

IATA Airport Abbreviations

IATA Airport Abbreviations

https://www.xkcd.com/1937

https://www.explainxkcd.com/wiki/index.php/1937:_IATA_Airport_Abbreviations

[A list with abbreviations and their meaning is shown in two columns.] [On top left the header reads:] Confused by those airport abbreviations used by your friends who fly a lot? Just memorize this list! [On top right an iMessage conversation is shown:] [There is a text in grey, on the left:] I'm flying into EWR tonight, then DTW tomorrow. [Answer (in blue, two message bubbles on the right):] Ok, cool I definitely know what those mean without Googling [The list:] AMD Amsterdam TMI Turkmenistan International BAE Beijing LAX Las Angalas ORD Orlando EWR Edwards Air Force Base IAD Idaho (Boise) PHL Pittsburgh JFC Jefferson City SWF Sherwood Forest IUD Washington Dulles KUL Kingdom of Loathing FYI Fayetteville STL Silent Hill LOL Louisville BUF Sunnydale ATL Atalante TBA Tribeca HGM Hogsmeade SMH Smithfield OMW Omaha BLT Baltimore ANC Ankh-Morpork YYY Toronto Downtown HSV Hunstville YYZ Toronto Pearson SAN San Diego MIA Colombo, Sri Lanka SAN San Juan CLT [Censored] SAN San Jose FHQ Fhqwhgads SAN San Francisco FFS Flagstaff Station SAN San Antonio DTF Dartford DWI Delaware International MDW Midway Atoll DFW Down for Whatever PDX Pordlanx DTW Down to Whatever SEA [Indicates Water Landing]

This comic is making fun of the three-letter codes assigned to mostly all airports in the world. These codes are overseen by the IATA (International Air Transport Association) . Some airport codes are very intuitive, taking letters from the city name (e.g., DEN for Denver ). Other codes are somewhat intuitive, taking a letter or two from the nearby city name but adding an additional letter (e.g., LAX for Los Angeles ). Other codes make seemingly no sense at all (e.g., ORD for Chicago's O'Hare International , due to it formerly being named Orchard Field). In many cases, the airport codes appear to have been chosen (or invented) because they are also common abbreviations and acronyms. Randall is obviously confused by these codes, replying to his friend that he definitely knows what those mean without googling, basically revealing that he used Google to search for the codes, and has created a list for us to memorize. In fact, this list is complete nonsense, with some of the "airports" mentioned not even existing, and the existing airports are all paired with the wrong codes, except for Huntsville (HSV) and Toronto Pearson (YYZ). If we use the table provided, Randall's friend is flying into Edwards Air Force Base and then "down to whatever" -- not a real flight. [ citation needed ] In actuality, the friend is flying into Newark tonight and Detroit tomorrow. The title text is a pun about the acronym IATA , stating it stands for I nternational A irpor T A bbreviation. This is as wrong as almost everything else here, because the real International Air Transport Association is not an organization only responsible for abbreviations in aviation. This acronym also leads to some redundancy in the title by making the true title of the comic be "International Airport Abbreviation Airport Abbreviations," which might be an example of RAS syndrome . This comic could be inspired by the recent news about an Indian businessman charged with making a bomb threat at a Mumbai airport claiming he was misheard by a telephone operator while asking for the BOM to DEL flight status. It may also be a reference to tongue-in-cheek ' teen texting code ' explanations for older generations. [A list with abbreviations and their meaning is shown in two columns.] [On top left the header reads:] Confused by those airport abbreviations used by your friends who fly a lot? Just memorize this list! [On top right an iMessage conversation is shown:] [There is a text in grey, on the left:] I'm flying into EWR tonight, then DTW tomorrow. [Answer (in blue, two message bubbles on the right):] Ok, cool I definitely know what those mean without Googling [The list:] AMD Amsterdam TMI Turkmenistan International BAE Beijing LAX Las Angalas ORD Orlando EWR Edwards Air Force Base IAD Idaho (Boise) PHL Pittsburgh JFC Jefferson City SWF Sherwood Forest IUD Washington Dulles KUL Kingdom of Loathing FYI Fayetteville STL Silent Hill LOL Louisville BUF Sunnydale ATL Atalante TBA Tribeca HGM Hogsmeade SMH Smithfield OMW Omaha BLT Baltimore ANC Ankh-Morpork YYY Toronto Downtown HSV Hunstville YYZ Toronto Pearson SAN San Diego MIA Colombo, Sri Lanka SAN San Juan CLT [Censored] SAN San Jose FHQ Fhqwhgads SAN San Francisco FFS Flagstaff Station SAN San Antonio DTF Dartford DWI Delaware International MDW Midway Atoll DFW Down for Whatever PDX Pordlanx DTW Down to Whatever SEA [Indicates Water Landing]

Meltdown and Spectre

Meltdown and Spectre

https://www.xkcd.com/1938

https://www.explainxkcd.com/wiki/index.php/1938:_Meltdown_and_Spectre

[Zoom out with Cueball and Ponytail walking to the right on the ground.] Cueball: The Meltdown and Spectre exploits use "speculative execution?" What's that? Ponytail: You know the trolley problem? Well, for a while now, CPUs have basically been sending trolleys down both paths, quantum-style, while awaiting your choice. Then the unneeded "phantom" trolley disappears. [Zoom in on only Ponytail who has turned towards Cueball off-panel left.] Ponytail: The phantom trolley isn't supposed to touch anyone. But it turns out you can still use it to do stuff. Ponytail: And it can drive through walls. [Cueball and Ponytail, lifting both her palms up, are standing, facing each other.] Cueball: That sounds bad. Ponytail: Honestly, I've been assuming we were doomed ever since I learned about Rowhammer. [In a frame-less panel they continue talking, both with their arms down.] Cueball: What's that ? Ponytail: If you toggle a row of memory cells on and off really fast, you can use electrical interference to flip nearby bits and— Cueball: Do we just suck at...computers? Ponytail: Yup. Especially shared ones. [Zoom out again as they resume walking to the right on the ground. Cueball is lifting his smartphone up and looks at the screen.] Cueball: So you're saying the cloud is full of phantom trolleys armed with hammers. Ponytail: ...Yes, that is exactly right. Cueball: Okay. I'll, uh... install updates? Ponytail: Good idea. Although this is clearly not part of the series Code Quality , it might be the same two characters, with Ponytail again displaying a much better understanding of computers than Cueball with his Computer Problems . The Trolley problem was mentioned a month before this comic in the last milestone on this list in 1925: Self-Driving Car Milestones ; see more there regarding why this problem might have resurfaced in xkcd. Three years before that comic, a comic was even named after the problem: 1455: Trolley Problem . The fact that compromising IT systems is sometimes easier done physically than logically is also mentioned in 538: Security .

This comic was inspired by the Meltdown and Spectre bugs found in certain processors; these vulnerabilities were disclosed to the public in the week of this comic. The bugs result from flawed implementations of speculative execution , and made big news because they broke the "walls" between programs executing concurrently on the same computer, in some circumstances allowing malware to steal secrets from normal, bug-free programs. Speculative execution is a technique used to speed up the execution of computer programs. Processors handle instructions in a series of steps , like an assembly line. The processor works on several successive instructions, each at a different stage in the assembly line. It may start speculatively executing instructions that follow a particular result of a decision before the execution of the logic that makes that decision is finished. Once the decision is made, it keeps results from the selected path, and discards unnecessary results. This allows it to keep doing useful work while some slower decision is made. In the Meltdown and Spectre bugs, the results of speculatively executed instructions are not completely discarded, allowing them to affect things that the program logic should have prevented. Ponytail uses the Trolley Problem , and trolley (tram) tracks in general, as an analogy for streams of instructions in a program. The Trolley Problem is a thought experiment where an out-of-control trolley is heading to a switch which you control. Leaving the switch as-is will cause it to kill multiple people (typically five) stuck on the tracks, but switching the track will cause it to kill only one person, who would not have died if the switch was left untouched. This creates the ethical dilemma of passively causing multiple deaths, versus actively causing one. The Trolley Problem has gained significant memetic traction, helped in no small part by its frequent inclusion in “introduction to philosophy” type courses. The problem has seen revitalized interest with the emergence of autonomous cars , which may be faced with what are, essentially, such choices in emergency situations. As an analogy for multiple mutually exclusive paths being executed at the same time, Ponytail invokes certain interpretations of quantum mechanics , where quantum-level particles can be viewed as taking every possible path at once, with the result being the sum of all of them. This is an idea popularized by the common interpretation of Schrödinger's cat , where the cat is both dead and alive until some event results in one of the states being selected. The phantom trolley driving through walls is an analogy for the computer instructions being able to access areas of memory that should be protected from them. This may also be a reference to quantum tunnelling , or even simply a joke about the phantom trolley being a literal phantom, i.e. incorporeal. In many cases, contrary to what the comic implies, both paths are not taken simultaneously during speculative execution. A branch predictor may be used to select the most likely path, and the effects should be completely erased if the predicted path is incorrect. Both branch prediction and taking both paths (known as eager evaluation) are considered speculative execution and are affected by these bugs. The Row hammer problem had been known for many years before this comic was published. A common form of computer memory is constructed from tiny capacitors organized in a two-dimensional grid of rows and columns. Capacitors store charge to represent information. By applying a pattern of memory access that rapidly changes a row of capacitors, you can cause charge to overflow to nearby rows and incorrectly change their states. Ponytail mentions that we especially suck at building "shared computers" because Row hammer, Spectre, and Meltdown all break down the security divisions built between programs and between users. A hacker running a separate program in a separate account shouldn't be able to access your data or change the behavior of your program, but these problems allow them to. This is particularly dangerous for time-sharing, servers, and the cloud , where different programs, websites, or even companies can be sharing the same hardware. Cueball takes her explanation literally, and comes to the conclusion that the cloud "is full of phantom trolleys armed with hammers", and Ponytail cannot be bothered correcting him. Cueball's final line ironically suggests that these exploits can be repaired with a simple software update. This seems to be mocking the naive misunderstanding that software can make up for flawed hardware. However, the exploits discussed in this comic are not trivial oversights, but reflect fundamental issues in the design of modern processors. A zero-day vulnerability is an attack that takes advantage of a vulnerability that hasn't been published yet, and so is not patched in any vulnerable system. The title text suggests that, until it was 'disclosed' here, nobody was aware that as well as Row hammer, computer servers can also be harmed by regular hammers. In reality, this would be obvious to most people. [ citation needed ] One might "patch" a server against this attack by plating it with stronger metal. [Zoom out with Cueball and Ponytail walking to the right on the ground.] Cueball: The Meltdown and Spectre exploits use "speculative execution?" What's that? Ponytail: You know the trolley problem? Well, for a while now, CPUs have basically been sending trolleys down both paths, quantum-style, while awaiting your choice. Then the unneeded "phantom" trolley disappears. [Zoom in on only Ponytail who has turned towards Cueball off-panel left.] Ponytail: The phantom trolley isn't supposed to touch anyone. But it turns out you can still use it to do stuff. Ponytail: And it can drive through walls. [Cueball and Ponytail, lifting both her palms up, are standing, facing each other.] Cueball: That sounds bad. Ponytail: Honestly, I've been assuming we were doomed ever since I learned about Rowhammer. [In a frame-less panel they continue talking, both with their arms down.] Cueball: What's that ? Ponytail: If you toggle a row of memory cells on and off really fast, you can use electrical interference to flip nearby bits and— Cueball: Do we just suck at...computers? Ponytail: Yup. Especially shared ones. [Zoom out again as they resume walking to the right on the ground. Cueball is lifting his smartphone up and looks at the screen.] Cueball: So you're saying the cloud is full of phantom trolleys armed with hammers. Ponytail: ...Yes, that is exactly right. Cueball: Okay. I'll, uh... install updates? Ponytail: Good idea. Although this is clearly not part of the series Code Quality , it might be the same two characters, with Ponytail again displaying a much better understanding of computers than Cueball with his Computer Problems . The Trolley problem was mentioned a month before this comic in the last milestone on this list in 1925: Self-Driving Car Milestones ; see more there regarding why this problem might have resurfaced in xkcd. Three years before that comic, a comic was even named after the problem: 1455: Trolley Problem . The fact that compromising IT systems is sometimes easier done physically than logically is also mentioned in 538: Security .

2016 Election Map

2016 Election Map

https://www.xkcd.com/1939

https://www.explainxkcd.com/wiki/index.php/1939:_2016_Election_Map

[A map of the United States, with Hawaii and Alaska offset, is shown. Across the states red, blue and green Cueball like stick figure are scattered about, much more on each coast, and very few in the central parts, especially in the mid west. There are about the same amount of red and blue stick figures. There are not many green, but they are represented almost in any state with more than 10 stick figures. Above the map there is a large bold title. Below that there is a legend description explaining the red, blue and green Cueball stick figure with labels of who they represent next to them. Below this, in light gray text, are two lines of explanation of how the map was created:] 2016 Election Map Each figure represents 250,000 votes [Red stick figure:] Trump [Blue stick figure:] Clinton [Green stick figure:] Other Based on 2016 election results Votes are distributed by states as accurately as possible while keeping national totals correct. Location within each state is approximate.

The United States elects its president not directly by popular vote but by an Electoral College composed of a number of electors, partially proportional to population, from each state. Presently, a "winner-take-all" system is used in most states: the winner of the popular vote in each state receives all of the electoral votes for that state. Though, strictly speaking, the electors are not required to cast their ballots according to this system, many states impose penalties on them if they don't. Technically, the popular vote in each state is to elect a slate of electors who in turn elect the President. Many Republicans tend to claim that Trump had a strong victory, and show maps filled with large, red counties. These maps look even redder than the state maps, so they make it look like Trump won a large nationwide victory. However, as Randall points, out, those maps are misleading, and using them to promote your candidate is a bit disingenuous. The news media commonly use maps to represent the progress or results of the election. Because of this winner-take-all system, states won by the Democratic candidate are typically portrayed in one color (blue is currently in wide use), and states won by the Republican candidate in another (currently red). In recent years, this distinction has gone far beyond electoral maps, and states are often referred to as "blue" or "red" by their political leaning in many contexts. Randall seems to be making a point on the shortcomings of both maps, by showing how different the actual vote was from the red and blue choropleth maps. He mentions how strange cartograms look, and by creating this map he hopes that it will convey the actual vote by geography well, while keeping the normal geographic boundaries. The title text repeatedly attempts and fails to spell the term choropleth map , a map that uses shading or colors to show information about a geographic area, such as a 'normal' election map that shows districts/states colored to the party that won them. In geography classes, "choropleth" is known as a chronically misspelled and mispronounced word. This is because the "choro" syllable sounds very similar to the Greek prefix "chloro", meaning "green in color" or "containing chlorine". The similar "pl" consonant cluster in the second syllable adds to this, resulting in metathesis . A choropleth map has many shortcomings. For example, many large Western states have small populations and thus don't make much difference to the electoral vote count, but look like a broad swath of red or blue on the map. The map overall can have the appearance of being very red or very blue, suggesting to the eye an overwhelming victory, when in fact the election can be extremely close. Donald Trump has repeatedly emphasized how red the map appears, especially when broken down by county, even though he actually lost the popular vote. In a speech on June 21, 2017, he said, "And those maps, those electoral maps, they were all red. Beautiful red." In this cartoon, Randall seems to be pointing out the shortcomings of the choropleth map (or perhaps this overall red-state/blue-state mentality). His map shows more clearly the small impact of the low-population states, as well as how combination of the winner-take-all system with the typical election maps fails to show the sometimes large number of opposition votes in a given state. This map also combines all third-party or independent candidate into one type of marker (green), making it clear that a substantial number of votes went to these candidates. A cartogram , also referenced in the title text, is a map that changes the size, and sometimes shape, of a region based on population or some other metric. Like a choropleth, these maps also have many shortcomings, the most obvious being the distortion required for the maps to work sometimes making it difficult to tell what and where the region actually is. Many versions of cartograms use squares to represent each region, with the size of the square corresponding to the metric measured. Often, it's easier to find specific places on these square maps. A similar map was actually used during the 2016 election by the Financial Times ( discussed here ). It made similar use of colorless states for geographic information and color in proportion to population for electoral information. However, the FT map is based on the electoral college, not the popular vote. It in turn is similar to a 2013 map used by The Guardian for the 2013 Australian election ( discussed here ). Other compromise maps of geographic and electoral information exist, such as maps of geographically accurate but re-scaled states: a 2016 election example is here , indirectly inspired by a similar vox.com map . Shortly after the election Randall made several comics that could indicate his emotions regarding the result, but references to the election have become fewer and farther apart. With a stick figure representing 250,000 votes, Trump would have exactly 251.918544 stick figures and Clinton would have exactly 263.37844 stick figures according to the final results . The map shows 252 Trump stick figures and 264 Clinton stick figures, meaning Randall used ceiling rounding instead of conventional rounding, which would have shown Clinton with one fewer stick figure. [A map of the United States, with Hawaii and Alaska offset, is shown. Across the states red, blue and green Cueball like stick figure are scattered about, much more on each coast, and very few in the central parts, especially in the mid west. There are about the same amount of red and blue stick figures. There are not many green, but they are represented almost in any state with more than 10 stick figures. Above the map there is a large bold title. Below that there is a legend description explaining the red, blue and green Cueball stick figure with labels of who they represent next to them. Below this, in light gray text, are two lines of explanation of how the map was created:] 2016 Election Map Each figure represents 250,000 votes [Red stick figure:] Trump [Blue stick figure:] Clinton [Green stick figure:] Other Based on 2016 election results Votes are distributed by states as accurately as possible while keeping national totals correct. Location within each state is approximate.

The Food Size Cycle

The Food Size Cycle

https://www.xkcd.com/1940

https://www.explainxkcd.com/wiki/index.php/1940:_The_Food_Size_Cycle

[There is a chart with the x-axis shown on top labeled "Food item size" and the y-axis labeled "Time". There are arrows pointing away from the top left corner on both axis.] The food size cycle [A normal sandwich is shown high up the chart. The text on the right reads:] Initial normal-sized food (sandwich, burger, burrito, taco, etc) [The next part below, further in time, has no pictured item but the text reads:] Food becomes more popular [Next below a larger sandwich is shown.] [And below again an even larger sandwich is shown. The text to the right is:] Size arms race: average item grows as restaurants compete to offer the largest version to hungry customers [On the left side, representing small food sizes, the text embedded in arrows pointing to every direction is:] Void [Below of that an enormously large sandwich is shown. The text is:] Food gets too large to eat comfortably [More below a new row on the left for small sizes comes up, inside is a panini. The text reads:] New format appears and fills the void (panini, burrito bowl, taquito, slider, etc) [Below of all the two paths may converge, indicated by two arrows pointing downwards and slightly together. The final text reads:] Merger or replacement

This comic illustrates the evolution of the size of food items over time, using the example of a sandwich. It starts with a regular sandwich at the beginning. As the sandwich became more popular, sandwich makers had an arms race concerning sandwich size as they competed for customers. Eventually, these sandwiches became too big to eat comfortably. At this point (according to Randall) some smart guy invented the panini, a small sandwich, to cater to those who couldn't find a sandwich small enough for their needs. Eventually, the panini itself will begin to grow, and either displace or become indistinguishable from the existing giant sandwiches, and the cycle will repeat. This is similar to Clayton Christensen's theory of disruption, where products keep adding features beyond what is needed by customers, and is then resolved by cheaper products with adequate features. The title text suggests that the same cycle may be applicable to the depth of pizza crust, with thin crusts being replaced with deeper and deeper ones, eventually necessitating a resurgence in thin crust. Randall laments that despite seeking funding to conduct experiments to test that hypothesis, he keeps getting turned down, probably because it sounds suspiciously like he wants to be paid for eating pizza. [There is a chart with the x-axis shown on top labeled "Food item size" and the y-axis labeled "Time". There are arrows pointing away from the top left corner on both axis.] The food size cycle [A normal sandwich is shown high up the chart. The text on the right reads:] Initial normal-sized food (sandwich, burger, burrito, taco, etc) [The next part below, further in time, has no pictured item but the text reads:] Food becomes more popular [Next below a larger sandwich is shown.] [And below again an even larger sandwich is shown. The text to the right is:] Size arms race: average item grows as restaurants compete to offer the largest version to hungry customers [On the left side, representing small food sizes, the text embedded in arrows pointing to every direction is:] Void [Below of that an enormously large sandwich is shown. The text is:] Food gets too large to eat comfortably [More below a new row on the left for small sizes comes up, inside is a panini. The text reads:] New format appears and fills the void (panini, burrito bowl, taquito, slider, etc) [Below of all the two paths may converge, indicated by two arrows pointing downwards and slightly together. The final text reads:] Merger or replacement

Dying Gift

Dying Gift

https://www.xkcd.com/1941

https://www.explainxkcd.com/wiki/index.php/1941:_Dying_Gift

[An old man (wrinkled and deformed head with a bit of hair left) is lying in his bed, head on a pillow, body beneath a blanket. He points to one of the three people standing along the side of the bed, Ponytail, Cueball, and a kid with spiky hair.] Old man: And to you... Old man: I leave the 30-foot Foucault Pendulum from the main hall. Old man: It has been swinging for fifty years. As long as you remember me, you must never let it stop! [Caption below the panel:] A fun prank: as you're dying, leave people gifts that will be as difficult as possible to put into storage.

In some cultures it is customary to make bequests, usually in written form called a will, of some or all of your possessions, to be given to people close to you after your death. Often, items bequeathed may be of purely sentimental value to the giver. That sentimental value may not carry over to the recipient, but they may, nonetheless, feel obliged to keep possession of them in order to respect the giver's wishes. In some cases, if the items are unwanted, unusable, or the recipient simply doesn't know what to do with them, they may elect to place the items in storage, rather than dispose of them. Randall therefore suggests the following prank to be played by someone near death: bequeath an item that is intentionally very difficult to store or even move. In this case, the old dying man gives his Foucault pendulum to someone in his family. A Foucault pendulum is a type of pendulum that is commonly used in science museums to practically demonstrate the rotation of the Earth. In order to attain the sensitivity required to do this, the pendulum must be very long - in this case, it is thirty feet (approximately nine meters) in length: about the height of a large hall. It must also be undisturbed; any disruption, such as a touch on the pendulum, will prevent it from accurately portraying the rotation of the Earth. By insisting that the pendulum never stop swinging, the old man has made it impossible for the pendulum to be simply detached and stowed away. Even transporting it will be extremely difficult, as it is thirty feet tall, and any change to its orientation will disrupt its swing. (Note, however, that the old man didn't specify that it has to work as a Foucault pendulum; merely, that it must not stop swinging.) He has also added an extra layer of guilt to the 'gift' by suggesting that if they do ever let it stop swinging it will be because they have forgotten him. The title text takes it even further, with a life-sized ice sculpture replica of the Pietà which was blessed by the Pope. A Pietà is a representation of the body of Jesus Christ on the lap of his mother, Mary , in the aftermath of his Crucifixion . When styled "The Pietà" it usually refers to Pietà a Renaissance sculpture by Florentine artist Michelangelo . It is widely considered one of the masterpieces of sculpture . While replicas of Pietà do exist, there are none known to have been made of ice , let alone made of ice and blessed by the Pope . That said, if such a sculpture were made, there are several ways to obtain a papal blessing. Such a sculpture would be over six feet tall and weigh several tons, and would have to be constantly maintained at sub-zero temperatures. While the gift could potentially be very valuable, the statement "all gifts must be removed from my estate within 24 hours" would dramatically increase its chances of melting. For both the pendulum and the ice sculpture, it is theoretically possible to devise a way to remove, transport, and store them with all the necessary conditions met, but they would probably be huge and very expensive logistical feats, requiring substantial planning and preparation. The final condition that everything must be removed within 24 hours makes such a feat practically impossible. As a side note: Catholic canon law would discourage selling such a sculpture and, were such a sculpture to melt, the water would need to be collected "burned, buried, or consumed". These are the proper ways to dispose of a blessed object. Alternatively, the title text could be read as meaning that there is a Pietà that has been blessed by the Pope, which formed the basis for this replica, though that would make the ice sculpture itself somewhat less remarkable. [An old man (wrinkled and deformed head with a bit of hair left) is lying in his bed, head on a pillow, body beneath a blanket. He points to one of the three people standing along the side of the bed, Ponytail, Cueball, and a kid with spiky hair.] Old man: And to you... Old man: I leave the 30-foot Foucault Pendulum from the main hall. Old man: It has been swinging for fifty years. As long as you remember me, you must never let it stop! [Caption below the panel:] A fun prank: as you're dying, leave people gifts that will be as difficult as possible to put into storage.

Memorable Quotes

Memorable Quotes

https://www.xkcd.com/1942

https://www.explainxkcd.com/wiki/index.php/1942:_Memorable_Quotes

Looking for a quote for something? Here are some for general use. They can be attributed to xkcd or Randall Munroe as needed. "I disagree strongly with whatever work this quote is attached to." "This quote was taken out of context." "This quote is often falsely attributed to Mark Twain." "I'm being quoted to introduce something, but I have no idea what it is and certainly don't endorse it." "This quote is very memorable." "I wrote this book, and the person quoting me here is taking credit for it." "This entire thing is the quote, not just the part in quote marks." [quote marks, brackets, and editor's note are all in the original. -ED.] "Websites that collect quotes are full of mistakes and never check original sources." "This quote will be the only part of this presentation you remember." "Oooh, look at me, I looked up a quote!" "If you're doing a text search in this document for the word 'butts,' the good news is that it's here, but the bad news is that it only appears in this unrelated quote." "Wait, what if these quote marks are inside out, so everything in the rest of the document is the quotation and this part isn't? Duuuuude." "The editors of Bartlett's Familiar Quotations are a bunch of cowards who don't have the guts to print this." "This quote only looks profound when it's in a script font over a sunset." "I don't do a lot of public speaking, so I looked up a memorable quote to start my speech, and this is what I found. OK, you're staring at me blankly, but this whole thing is a quote. I know that sounds confusing, but... You know what, never mind!" "Sent from my iPhone."

This comic "helpfully" provides random quotes to be used by anyone as blurbs , online reviews, motivational quotes or similar short bits of text. Either the webcomic xkcd or its creator Randall Munroe may be quoted when using any of the provided lines, as stated at the top of the comic. In particular, their "usefulness" lies in the fact that almost any of them are equally applicable to almost any situation. This is achieved by making each quote not really about anything in particular, aside from the fact that they are quotes. This is in contrast to typical quotes, which are never quite this aware that they will be quoted, but this is to be expected when the lines here were made solely for being quoted. These self-aware quotes are, on a meta level, jokes about quotations generally. Most of Randall's quotes either sabotage the quoting work, reference some aspect of quotes as used in practice, or both---and it can be both when the aspects referenced are about twisting people's words to look like they agree with you. The title-text does not have an ending quote mark, so "- Randall Munroe" is part of the quote, and possibly everything in xkcd after that until the next ending quote. Note that the next quote mark in xkcd is in 1946: Hawaii . Looking for a quote for something? Here are some for general use. They can be attributed to xkcd or Randall Munroe as needed. "I disagree strongly with whatever work this quote is attached to." "This quote was taken out of context." "This quote is often falsely attributed to Mark Twain." "I'm being quoted to introduce something, but I have no idea what it is and certainly don't endorse it." "This quote is very memorable." "I wrote this book, and the person quoting me here is taking credit for it." "This entire thing is the quote, not just the part in quote marks." [quote marks, brackets, and editor's note are all in the original. -ED.] "Websites that collect quotes are full of mistakes and never check original sources." "This quote will be the only part of this presentation you remember." "Oooh, look at me, I looked up a quote!" "If you're doing a text search in this document for the word 'butts,' the good news is that it's here, but the bad news is that it only appears in this unrelated quote." "Wait, what if these quote marks are inside out, so everything in the rest of the document is the quotation and this part isn't? Duuuuude." "The editors of Bartlett's Familiar Quotations are a bunch of cowards who don't have the guts to print this." "This quote only looks profound when it's in a script font over a sunset." "I don't do a lot of public speaking, so I looked up a memorable quote to start my speech, and this is what I found. OK, you're staring at me blankly, but this whole thing is a quote. I know that sounds confusing, but... You know what, never mind!" "Sent from my iPhone."

Universal Dreams

Universal Dreams

https://www.xkcd.com/1943

https://www.explainxkcd.com/wiki/index.php/1943:_Universal_Dreams

[Megan, Ponytail, and Black Hat are standing around.] Megan: I've been out of school for years, but I still get those dreams where I have an exam and I didn't prepare. [Ponytail shrugs.] Ponytail: I think that's one of those weird universal dreams— like forgetting your clothes or discovering rooms in your house you didn't know about. [Zoom-in on Black Hat.] Black Hat: Yeah! Or when you're having a normal dream, but then a horse appears on a distant hilltop, and it means that the dream is about to turn bad! Ponytail or Megan (off-screen): I... What? Black Hat: I have that one like every night. [Megan and Ponytail look at Black Hat.] Black Hat: Or those ones where you're talking to someone, and they start repeating a latitude and longitude over and over, and then you wake up that morning and there's an earthquake there. Black Hat: Haha, dreams, right? So weird! Dreaming of latitude and longitude was also a topic of 240: Dream Girl , but in contrast to this comic, the events in that dream did not come true within the comic. (However, a real-life meetup of xkcd fans occurred at the location and date mentioned within the comic.)

The first and second panel are a discussion between Megan and Ponytail about dreams . Megan mentions a dream or nightmare about failing to prepare for an exam, despite not being a student for years. This is similar to the dream depicted in 557: Students . Ponytail responds that certain dreams occur with surprising frequency among many people, dubbing them "Universal Dreams" (which is the title of the comic). Universal dreams are dreams that are weirdly common, as also abused in 719: Brain Worms . In the third panel, Black Hat describes an avatar of misfortune in the form of a horse appearing on a hill. This could be a play on the word nightmare . A mare was originally a demon or goblin that gave bad dreams. The modern word mare , meaning female horse, has a different origin, but still serves handily as a homophonic pun . Alternatively, this may be a reference to the 2007 film Michael Clayton , which features a dreamlike sequence where the title character recognizes a scene of three horses on a hilltop from an illustration in a book. He stops his car, gets out and approaches the horses, just minutes before his car explodes. This marks a major turning point in the direction Clayton takes for the rest of the film, similar to how Black Hat says "[the horses] mean the dream is about to turn bad." In the last panel, Black Hat describes having dreams where he receives specific information about the real world, which seems closer to prophesying or precognition than what would be considered a normal dream, as normal dreams do not tell the future. [ citation needed ] This may be a reference to the 2009 film Knowing , in which a child hears voices telling her the date, time, latitude, and longitude of major disasters (including earthquakes) that will occur 50 years in the future. This could also be a reference to comic 240 . In the title text, either Megan or Ponytail is responding to Black Hat when she unexpectedly interrupts herself with the first part of geographic coordinates (Latitude 35), just as Black Hat described, implying that the whole comic might be another of Black Hat's dreams. 35 degrees North would include 31 major cities around the world, including 11 in Japan and 8 in the USA (including California, a seismically active region); the only major city within 35 degrees South is Canberra, Australia. This would suggest that an earthquake would happen soon in one of those major cities. The remainder of the coordinates are most likely cut off to add uncertainty to the situation. [Megan, Ponytail, and Black Hat are standing around.] Megan: I've been out of school for years, but I still get those dreams where I have an exam and I didn't prepare. [Ponytail shrugs.] Ponytail: I think that's one of those weird universal dreams— like forgetting your clothes or discovering rooms in your house you didn't know about. [Zoom-in on Black Hat.] Black Hat: Yeah! Or when you're having a normal dream, but then a horse appears on a distant hilltop, and it means that the dream is about to turn bad! Ponytail or Megan (off-screen): I... What? Black Hat: I have that one like every night. [Megan and Ponytail look at Black Hat.] Black Hat: Or those ones where you're talking to someone, and they start repeating a latitude and longitude over and over, and then you wake up that morning and there's an earthquake there. Black Hat: Haha, dreams, right? So weird! Dreaming of latitude and longitude was also a topic of 240: Dream Girl , but in contrast to this comic, the events in that dream did not come true within the comic. (However, a real-life meetup of xkcd fans occurred at the location and date mentioned within the comic.)

The End of the Rainbow

The End of the Rainbow

https://www.xkcd.com/1944

https://www.explainxkcd.com/wiki/index.php/1944:_The_End_of_the_Rainbow

[Megan and Cueball are walking.] Megan: There's a pot of gold at the end of the rainbow. Cueball: Rainbows are circles. They have no end. Megan: Not quite! [In a borderless panel, a multi-part graphic is shown depicting what Megan is describing off-panel: a short cone inside a longer cone, with the longer cone having its point starting at the Sun, the shorter cone having its point at a miniature Cueball's head, and both cones sharing the same circular base. The diagram is repeated from 3 different perspectives to make the structure easier to grasp.] Megan (off-panel): A rainbow is light leaving the Sun, bouncing off the clouds, and converging on your eye. It's an inside-out two-ended cone. [Megan and Cueball are still walking.] Megan: One end of that cone is your retina. [A wider view of the same scene, with Megan and Cueball walking on a dark ground.] Megan: The other end is the Sun—which contains quintillions of tons of gold. There's more gold in the Sun than water in the oceans. Cueball: So there is a pot of gold! Cueball: What about leprechauns? Megan: All incinerated as the sun formed. Very sad. As of January 19, 2017, the value of gold is 42,692.98 USD per kilogram. Based on this, all of the gold in the sun is worth 2.5474901 × 10^22 (25 sextillion 474 quintillion 901 quadrillion) USD. Of course, if you tried to sell the gold in the sun, the market would be saturated and the value of gold would plummet astronomically. You would never be able to cash out. The idea that the Sun is valuable in monetary terms is also present in 1622: Henge .

Megan appears to reference the myth that at the end of every rainbow lies a leprechaun 's pot of gold. Instead of claiming that leprechauns and their gold don't exist, Cueball offers the refutation that, technically, rainbows are circles , so they do not have an end. This is true for an idealised rainbow, and for some actual rainbows: if the viewer has an unobstructed view of the light-reflecting substance creating the effect for the whole of the circle's circumference, they could see a full circle. In practice, the circle is often broken by the horizon or, for example, discontinuity in cloud cover. However, Megan counters that if one considers the path that light takes to form a rainbow, then it forms a two-cone structure, where the Sun (the vertex of the outer cone) emits light rays that move towards the Earth (forming the faces of the outer cone), then reflect off water droplets located at just the right angle (the circular base) to reach our eyes (the vertex of the inner cone). Thus, such a rainbow structure can be said to have "ends", represented by the vertices of the two cones: one at the eye of the viewer, and another at the light source (usually the sun). A common rainbow (which base is formed by a water droplets in the Earth's atmosphere) can not be viewed as that. The Sun's diameter is orders of magnitude greater than Earth's one (even including the outer layers of the atmosphere), and we would expect the apex of a cone to be much smaller than its base. Thus a two-cone rainbow which starts in Sun shall have its base formed in the outer space. Megan then says that the Sun is indeed a pot of gold. The Sun is approximately 1.989 × 10 30 (1 nonillion 989 octillion) kilograms , and its abundance of gold is approximately 0.3 parts per trillion (ed: this value is incorrect - values in the paper are not in ppt - see comments below). Based on these numbers, the sun contains 5.967 × 10 17 (596 quadrillion 700 trillion) kilograms of gold. This equates to 5.967 × 10 14 (596 trillion 700 billion) metric tons of gold. As such, Megan's statement that the sun contains "quintillions of tons of gold" is off by a factor of roughly 4000, but the amount of gold within the sun is, nonetheless, far more than a pot's worth. [ citation needed ] The amount of water in the oceans is about 1.35 × 10 18 (1 quintillion 350 quadrillion) metric tons . If we assume that Megan is still talking in terms of mass rather than volume or molecule count, then her next statement (that there is more gold in the sun than water in the oceans) would have been true had she been correct in her previous claim, but in fact there is more sea-water than sun-gold by a factor of roughly 2300. Cueball then asks about leprechauns (perhaps ironically, since Megan's theory at this point appears to involve astronomy/physics, not mythical creatures/beings). Megan replies that the leprechauns all died when the Sun formed, building on the irony of Cueball's question (& opening questions about the role of leprechauns in the early formation of our solar system). The title text suggests that, since the pot of gold exists as an idea in the brains of people thinking about it, and the retina is the foremost part of the brain for light perception, it can be argued that, in addition to existing in the sun as the comic explains, the gold (and leprechauns) also exist at the perceiver's end of the cone, as long as they are thinking about a pot of gold at the time (and then it's gone as soon as they stop thinking about it). Many neurologists would agree with the concept that ideas in your mind can be said to be physically located in your brain. However, this seems to go further, and suggest an idealist ontological position, that things, in this case a pot of gold, exist by virtue of our having an idea of them. [Megan and Cueball are walking.] Megan: There's a pot of gold at the end of the rainbow. Cueball: Rainbows are circles. They have no end. Megan: Not quite! [In a borderless panel, a multi-part graphic is shown depicting what Megan is describing off-panel: a short cone inside a longer cone, with the longer cone having its point starting at the Sun, the shorter cone having its point at a miniature Cueball's head, and both cones sharing the same circular base. The diagram is repeated from 3 different perspectives to make the structure easier to grasp.] Megan (off-panel): A rainbow is light leaving the Sun, bouncing off the clouds, and converging on your eye. It's an inside-out two-ended cone. [Megan and Cueball are still walking.] Megan: One end of that cone is your retina. [A wider view of the same scene, with Megan and Cueball walking on a dark ground.] Megan: The other end is the Sun—which contains quintillions of tons of gold. There's more gold in the Sun than water in the oceans. Cueball: So there is a pot of gold! Cueball: What about leprechauns? Megan: All incinerated as the sun formed. Very sad. As of January 19, 2017, the value of gold is 42,692.98 USD per kilogram. Based on this, all of the gold in the sun is worth 2.5474901 × 10^22 (25 sextillion 474 quintillion 901 quadrillion) USD. Of course, if you tried to sell the gold in the sun, the market would be saturated and the value of gold would plummet astronomically. You would never be able to cash out. The idea that the Sun is valuable in monetary terms is also present in 1622: Henge .

Scientific Paper Graph Quality

Scientific Paper Graph Quality

https://www.xkcd.com/1945

https://www.explainxkcd.com/wiki/index.php/1945:_Scientific_Paper_Graph_Quality

[Heading on top of the graph:] General quality of charts and graphs in scientific papers [A graph is shown with the y-axis on the origin labeled "bad", on the arrowhead labeled "good", and the x-axis being a timeline labeled with decades from 1950s to 2010s.] [The pre-1993 and post-2015 parts are white, with increasing quality before 1990 and after 2015. The 1993-2015 part indicates bad quality and is highlighted in grey, labeled "PowerPoint/MSPaint era".]

Microsoft Paint was first introduced in 1985 as a component of Windows 1.0 , and Microsoft PowerPoint debuted in 1990. As easy-to-use tools, these allowed for the easy creation of graphs by computer users. The comic implies that these are responsible for decreasing the overall quality of graphs in scientific papers, presumably by enabling a large number of inexperienced designers, and encouraging certain kinds of designs that are ineffective for communicating scientific results. Critics of PowerPoint , such as Edward Tufte , have argued that the software is ill-suited for reporting scientific analyses. Many scientific journals nowadays explicitly forbid the use of PowerPoint in their instructions for authors. It can be argued that other software specifically built for this task - and techniques to do so - have been refined over time, leading to a rise in graph quality outside the PowerPoint/MSPaint era (though see discussion). The title text states that among the bad quality graphs, the ones “with qualitative, vaguely-labeled axes and very little actual data” are the worst. While this may indicate that the problem with PowerPoint era graphs is that they seem to focus on getting the point across (qualitative as in “you get the idea”) over accuracy (little actual data), this is more hypocritical humor on Randall's part, as the comic itself features exactly that sort of lambasted graph. The vertical axis labeled “good” and “bad” is entirely qualitative, the horizontal axis manages to use numbers and still be vague by labeling the area between the ticks as decades instead of labeling the ticks, the definition of what constitutes the ‘PowerPoint / MSPaint era’ is entirely unclear, and it is doubtful that any actual data was used to make the graph – certainly there are no actual data points indicated. Its quality is doubtful, and it might represent more of an impression, or opinion, than an actual fact. [Heading on top of the graph:] General quality of charts and graphs in scientific papers [A graph is shown with the y-axis on the origin labeled "bad", on the arrowhead labeled "good", and the x-axis being a timeline labeled with decades from 1950s to 2010s.] [The pre-1993 and post-2015 parts are white, with increasing quality before 1990 and after 2015. The 1993-2015 part indicates bad quality and is highlighted in grey, labeled "PowerPoint/MSPaint era".]

Hawaii

Hawaii

https://www.xkcd.com/1946

https://www.explainxkcd.com/wiki/index.php/1946:_Hawaii

[Cueball is standing, slightly crouched, at a desk with one hand on a laptop and the other holding his phone.] Off-screen voice: Hurry! Cueball: It keeps saying "Wrong Password!" I've tried everything it might be! Off-screen voice: The clock is ticking! Cueball: I requested a reset but haven't gotten it! Which email did I use?! Off-screen voice: Sirens are going off!! Cueball: It's not in my password manager! Is it in a browser? Which browser? Is Autofill synced to my phone?? Off-screen voice: OH MY GOD THE SCREAMING!! [Caption below the panel:] I feel bad for everyone in Hawaii, but when the governor couldn't get into his Twitter account, he lived out one of my very specific nightmares in real life. The Hawaii emergency agency also might have password problems. In a news article from June 2017 there was a photo showing an agency employee standing beside his own computer, which sports a password on a sticky note. This caused further criticism of the agency security practices .

On January 13, 2018, the state of Hawaii sent out an emergency alert warning of an incoming ballistic missile attack. The message was specifically noted to NOT be a drill. This caused widespread panic and fear amongst the island residents, and there were follow-up confirmations from local entities who thought the original warning was real. It was eventually determined that the alert was sent in error -- the explanation being that a technician accidentally sent out the "real" version when they were supposed to be testing the system during an end-of-shift changeover -- but the fact that it took around 15 minutes for the correction to be sent drew widespread criticism. On January 23, it was revealed that the governor of Hawaii knew the alert was a false alarm only two minutes after it was sent, but couldn't notify the public because he had forgotten the login information for his Twitter account. The proliferation of online services requiring authentication, together with variations in security requirements, various flavours of Multi-factor authentication , a variety of password retrieval methods, and security advice not to re-use passwords across services, has resulted in the management and memorisation of passwords becoming a major headache for many people. This comic shows Cueball, representing the governor, frantically trying to retrieve his log in to Twitter and encountering a number of common frustrations: Off-panel, another person is adding to the stress of his situation by screaming at him that people are beginning to panic and warning sirens are going off, underscoring the need to get the correction out as fast as possible. As the caption under the comic indicates, Randall has had a nightmare along these (very specific) lines, and is amused to find someone experiencing that nightmare in the real world. The alt-text refers to USB security keys, physical USB devices that act as tangible 'passwords' for various accounts or devices. (A traditional key of shaped metal is literally a tangible password, with each digit of the password releasing one tumbler of a physical lock; Electronic keys replace the key-and-tumbler password system with a digital password signal.) In the context of this comic, the governor attempts to sign into his Twitter account using one such key, but can't insert it into his computer correctly (as USB devices are infamous for needing to be inserted in a particular orientation despite having a symmetrical outer appearance; also known as USB superposition .) Trying to flip the key around, Cueball drops it into a vent - similar to what happens in 1518: Typical Morning Routine . [Cueball is standing, slightly crouched, at a desk with one hand on a laptop and the other holding his phone.] Off-screen voice: Hurry! Cueball: It keeps saying "Wrong Password!" I've tried everything it might be! Off-screen voice: The clock is ticking! Cueball: I requested a reset but haven't gotten it! Which email did I use?! Off-screen voice: Sirens are going off!! Cueball: It's not in my password manager! Is it in a browser? Which browser? Is Autofill synced to my phone?? Off-screen voice: OH MY GOD THE SCREAMING!! [Caption below the panel:] I feel bad for everyone in Hawaii, but when the governor couldn't get into his Twitter account, he lived out one of my very specific nightmares in real life. The Hawaii emergency agency also might have password problems. In a news article from June 2017 there was a photo showing an agency employee standing beside his own computer, which sports a password on a sticky note. This caused further criticism of the agency security practices .

Night Sky

Night Sky

https://www.xkcd.com/1947

https://www.explainxkcd.com/wiki/index.php/1947:_Night_Sky

[Cueball and Megan are walking under the night sky.] Megan: The internet is so overwhelming for me these days. It feels like everyone I know is yelling all the time. [Frame is zoomed out. Stars are visible in the sky.] Megan: That's why it's so nice to unplug. Leave the phones at home, go for a walk, and look up at the stars. Megan: It helps you focus on what really matters. [Frame is zoomed in again.] Cueball: Like "Where the hell are we?" Megan: And "Why did I leave my phone at home? It has my map and flashlight." Cueball: "Are there mountain lions around here? Did you hear a twig break?" Megan: Yeah, the big questions!

With the increasing ubiquity of connected devices in people's lives have come concerns about the social and mental effects this is having. A common trend in lifestyle advice is the idea of " unplugging " and getting away from technology, with the idea that this can improve one's sense of wellbeing, and allow a focus on the important things in life, such as asking the "big" existential questions . Cueball and Megan are taking one such activity: a nighttime walk without their phones. However, rather than being grandiose, the questions they ask are increasingly immediate to their current situation. Far from finding the experience liberating, they find it first frustrating, as they no longer have access to useful features of their phones, such as mapping with GPS, which would help them find their way, and a flashlight, which would let them see where they were going, and then unsettling, as without their devices to distract them they begin to imagine dangers, such as mountain lions , lurking in the darkness. The fact that Megan enthusiastically affirms that those really are the "big questions" of life reveals that they are sarcastically teasing each other about their regrettable decision. The reference to mountain lions might be related to the declaration that eastern cougars were officially declared extinct the day before this comic was published. The title text claims that technology is so omnipresent that even the threatening mountain lion has a phone and is reading Facebook (and, therefore, is not so threatening, since it now can not notice them). Alternatively, either Cueball or Megan might be teasing the other. [Cueball and Megan are walking under the night sky.] Megan: The internet is so overwhelming for me these days. It feels like everyone I know is yelling all the time. [Frame is zoomed out. Stars are visible in the sky.] Megan: That's why it's so nice to unplug. Leave the phones at home, go for a walk, and look up at the stars. Megan: It helps you focus on what really matters. [Frame is zoomed in again.] Cueball: Like "Where the hell are we?" Megan: And "Why did I leave my phone at home? It has my map and flashlight." Cueball: "Are there mountain lions around here? Did you hear a twig break?" Megan: Yeah, the big questions!

Campaign Fundraising Emails

Campaign Fundraising Emails

https://www.xkcd.com/1948

https://www.explainxkcd.com/wiki/index.php/1948:_Campaign_Fundraising_Emails

[An e-mail inbox window is displayed. On each line appears an illegible e-mail address and a checkbox.] Donate now. It's crunch time, and we're low on cash. If you chip in just $5 by midnight, we… Donate $35.57 now! Our data team has determined that we should ask you for $35.57 to optimize the… Help. Our campaign made some mistakes and we need a lot of money ASAP. Any kind, but cash is… Washington is broken. When I win, I'll look those other senators in the eye and tell them: "Jobs." Then I… Hopeless. It's bad. Really bad. If you don't chip in now, the darkness spreading across the land will… As the first woman to fly a fighter jet through our state's formerly all-male university, I learned… We're broke. No paid staff. No ads. And the cafe has told us to stop using their wifi to send fundraising… When Amy decided to run for Congress, I was like "Huh?" but I checked Wikipedia, and apparently it's a branch of… Are you familiar with the Dutch painter Hieronymous Bosch? His work illustrates my opponent's plan for… Being a single mom running a small business while going to law school while being deployed to Iraq taught me… I will lead the fight against the big banks, special interests, the Earth's climate, and our children. I… Wow. Have you seen this video of the squirrel obstacle course? Incredible! Anyway, I'm running because I… Outrageous. Granted, this was a few years ago, but did you hear what President Ford said about… Whoops. Due to a typo, we spent months running attack ads against Tom Hanks. Now, we need to make up for… They say we can't win— that we're "underdogs" with "no money" who "lost the election last week." But they don't… Our campaign's only chance is to seduce Jennifer ActBlue, heir to the ActBlue fortune. For that, we need a fancy… Doom. Where is the horse and the rider? Where is the horn that was blowing? They have passed, like rain on… Warmest greetings. I am the crown prince of Nigeria. I am running for Congress because I believe that…

Many politicians and organizations in the United States have taken to using email to conduct aggressive fundraising drives seeking campaign contributions. Signing a petition or expressing interest in a cause can lead to being added to a myriad of mailing lists for similar groups, all looking for support. This comic shows a caricature of the kind of inbox that can result from this. The emails get more and more absurd as the list goes on. For example, the last one combines a request for campaign contributions with the infamous 'Nigerian prince' advance-fee scam phishing scheme. [An e-mail inbox window is displayed. On each line appears an illegible e-mail address and a checkbox.] Donate now. It's crunch time, and we're low on cash. If you chip in just $5 by midnight, we… Donate $35.57 now! Our data team has determined that we should ask you for $35.57 to optimize the… Help. Our campaign made some mistakes and we need a lot of money ASAP. Any kind, but cash is… Washington is broken. When I win, I'll look those other senators in the eye and tell them: "Jobs." Then I… Hopeless. It's bad. Really bad. If you don't chip in now, the darkness spreading across the land will… As the first woman to fly a fighter jet through our state's formerly all-male university, I learned… We're broke. No paid staff. No ads. And the cafe has told us to stop using their wifi to send fundraising… When Amy decided to run for Congress, I was like "Huh?" but I checked Wikipedia, and apparently it's a branch of… Are you familiar with the Dutch painter Hieronymous Bosch? His work illustrates my opponent's plan for… Being a single mom running a small business while going to law school while being deployed to Iraq taught me… I will lead the fight against the big banks, special interests, the Earth's climate, and our children. I… Wow. Have you seen this video of the squirrel obstacle course? Incredible! Anyway, I'm running because I… Outrageous. Granted, this was a few years ago, but did you hear what President Ford said about… Whoops. Due to a typo, we spent months running attack ads against Tom Hanks. Now, we need to make up for… They say we can't win— that we're "underdogs" with "no money" who "lost the election last week." But they don't… Our campaign's only chance is to seduce Jennifer ActBlue, heir to the ActBlue fortune. For that, we need a fancy… Doom. Where is the horse and the rider? Where is the horn that was blowing? They have passed, like rain on… Warmest greetings. I am the crown prince of Nigeria. I am running for Congress because I believe that…

Fruit Collider

Fruit Collider

https://www.xkcd.com/1949

https://www.explainxkcd.com/wiki/index.php/1949:_Fruit_Collider

[Ponytail points with a stick at a graph hanging on the wall. It depicts a collision of two apples producing a banana, a bunch of grapes, a cherry, three strawberries, and one product which is too small to distinguish clearly but which may be a single grape or berry.] Ponytail: When two apples collide, they can briefly form exotic new fruit. Pineapples with apple skin. Pomegranates full of grapes. Watermelon-sized peaches. Ponytail: These normally decay into a shower of fruit salad, but by studying the debris, we can learn what was produced. Ponytail: Then, the hunt is on for a stable form. [Caption below the panel:] How new types of fruit are developed Randall has previously indicated that he finds pineapple tasty but very hard to eat in 388: Fuck Grapefruit . This comic was published on the Jewish holiday for the trees, Tu BiShvat (Hebrew: טו בשבט) , on which it is traditional to eat exotic fruits.

Ponytail is suggesting that exotic new fruit can be created in a similar way to that in which exotic subatomic particles can, by smashing together more common varieties at high speed. Particle accelerators are used to smash sub-atomic particles together at near-light speeds. This can result in a release of enough energy to produce massive exotic particles that do not exist under standard conditions. By examining the results, physicists can test theories in physics and, sometimes, unexpected consequences can force them to revise existing theories. When explaining particle accelerators to the general public, this kind of experiment is sometimes explained with a fruit analogy. For example, the University of Oxford's " Accelerate! " show says "It's like throwing together two apples really really hard and getting three bananas and a mango." In this comic strip, the analogy is taken literally, and claims that several interesting new types of fruit have been created. Pineapples with apple skin. The tough, spiny skin of pineapples makes them (almost) impossible to eat without a knife and, while high in fiber, can be a danger to the intestinal tract and is commonly considered inedible. Nevertheless, many people really like the taste of them. Creating a variety with the skin of an apple would allow them to be enjoyed without the usual inconvenience. Pomegranates full of grapes . A pomegranate is a large berry containing a large number of seeds with fleshy coverings. Many people find the high seed-to-flesh ratio offputting when eating them. If these were replaced with grapes, this ratio would be much lower; if it were a seedless variety of grape, it could be zero. Watermelon -sized peaches . This could be a reference to the Roald Dahl story James and the Giant Peach , or Randall may just really like peaches, as shown in 388: Fuck Grapefruit . Strawberry banana [title text] Strawberry and banana is a popular flavor combination for yogurts and smoothies. The "massive collider" in Europe refers to the Large Hadron Collider , the largest particle accelerator in the world. However the Large Hadron Collider was built to investigate the relationship between matter and forces [1] , and not to search for a strawberry banana [ citation needed ] . Many fruit-based snacks and drinks will derive flavors from fruit blends. These are generally created by mixing the juice, or artificial substitute flavorings, of two separate, individual fruits, rather than by attempting to create a new fruit by smashing the constituent fruits together. Some man-made hybrid fruits have been created via cross-breeding, grafting, and genetic engineering. It is notable that fruiting plants are generally far more capable of mixing genes across species than animals are. It is often quite possible to produce a hybrid of two fairly distantly related fruits by forcing the pollen of one to fertilize the ovary of another, or even splicing the bulk of the genes together. Of course, this would be more likely to happen in a high-energy collision of their reproductive parts, rather than their fruits. Smashing two fruits together at high speeds will usually result in a sticky mess rather than a new fruit hybrid, as recognised in the title text. It should be noted that the hypothesis presented in this strip has now been tested by The Slow Mo Guys . [Ponytail points with a stick at a graph hanging on the wall. It depicts a collision of two apples producing a banana, a bunch of grapes, a cherry, three strawberries, and one product which is too small to distinguish clearly but which may be a single grape or berry.] Ponytail: When two apples collide, they can briefly form exotic new fruit. Pineapples with apple skin. Pomegranates full of grapes. Watermelon-sized peaches. Ponytail: These normally decay into a shower of fruit salad, but by studying the debris, we can learn what was produced. Ponytail: Then, the hunt is on for a stable form. [Caption below the panel:] How new types of fruit are developed Randall has previously indicated that he finds pineapple tasty but very hard to eat in 388: Fuck Grapefruit . This comic was published on the Jewish holiday for the trees, Tu BiShvat (Hebrew: טו בשבט) , on which it is traditional to eat exotic fruits.

Chicken Pox and Name Statistics

Chicken Pox and Name Statistics

https://www.xkcd.com/1950

https://www.explainxkcd.com/wiki/index.php/1950:_Chicken_Pox_and_Name_Statistics

[The first panel shows graph with only the x-axis labeled and with seven labeled ticks. The y-axis has three ticks with percentage labels. A red line rises from bottom to top as it goes from left to right. There is an arrow pointing at the graph with a label. Above the left part of the red line there is a title and beneath that a reference to the source of the data in gray font.] [According to the graph, the percentage is close to 0 for ages below 15 and close to 100 for ages above 30.] Fraction of kids your age who got chicken pox (Very rough US estimates based on DOI:10.15585/mmwr.mm6534a4 and DOI:10.1016/j.vaccine.2012.05.050) 100% 50% 0% Your age: 5  10  15  20  25  30  35 Vaccine introduced in 1995 [The second panel shows a graph with only the x-axis labeled and with seven labeled ticks. The graph has six gray lines with labels on them. To the right is a title and beneath that a reference to the source of the data in gray font.] [According to the graphs, Sarah and Brian are more popular names for older age groups.] Relative popularity of several names in your age group (Source: ssa.gov) Harper Sarah Jaxon Brian Brooklyn Logan Your age: 5  10  15  20  25  30  35 [The third panel shows a list of names with a percentage next to them. Above the list is a title and beneath that a statement in gray font:] Chicken pox incidence by name: (Very rough estimate) Brian: 75% Sarah: 60% Logan: 20% Brooklyn: 10% Jaxon: 4% Harper: 2% [Caption below the panels:] Fun Fact: People named "Sarah" and "Brian" think chicken pox is normal and common, and people named "Logan" and "Harper" do not.

This is another comic with one of Randall's fun facts . In this comic statistics are used to point out some non-intuitive correlations. The first panel sketches out the prevalence of chicken pox by age in the United States . As the graph indicates, prior to the introduction of the varicella vaccine in the United States, it was an exceptionally common childhood illness, with almost 100% of the population experiencing it at some point. The illness is highly memorable (since the symptoms last for days and are intensely uncomfortable) and noticeable (since the characteristic blisters are distinctive and difficult to hide), meaning that it was once a common experience that people expected to both experience and see in their peers. As the vaccine became widespread in the US, rates of varicella infection declined dramatically, and new infections are now relatively uncommon. The graph points out that this has led to a fundamental shift in experiences by age. For an American over the age of 30, nearly all your peers growing up would have had chicken pox. For an American under the age of 10, virtually none of them would have had it. This means that older people are likely to think of chicken pox as a normal part of life, while children are likely to have no experience with it, and may not even know what it is. The second, seemingly unrelated graph, charts the popularity of certain names over time, in the US. It's normal and expected for certain names to rise and fall in popularity over time, which means that the number of people with those names ends up clustered by age. The names "Sarah" and "Brian" have gone from being highly popular to relatively uncommon for new babies, meaning that people with those names are much likelier to be older. Names like "Logan", "Brooklyn", "Jaxon" and "Harper" went from being virtually unused to having a spurt of popularity, meaning that (as of 2018) people with those names are much more likely to be under the age of 15 than over it. The final panel points out that these trends, taken together, generate the interesting effect that you can, in some cases, estimate the odds of someone having had chicken pox, based solely on their first name. Having a name like "Brian" or "Sarah" raises the odds that you're over 30, which raises the odds that you had chicken pox. People named "Harper" or "Jaxon" are almost certainly young enough to have grown up with the vaccine in broad use. These time-based trends predict both the odds of a person having had the illness personally, and the odds that they grew up in a time when infections were common and generally expected. The cartoon demonstrates the correlative fallacy, i.e. what can go wrong if one attempts to draw conclusions based on a random comparison of two variables, as described by the famous saying: " Correlation does not imply causation ". In this case, there's a real correlation between names and the incidence of a particular disease. A superficial reading could suggest that either certain names make people prone to the disease, or that the disease, in some way, impacts a person's name. The real cause of this correlation is simply that certain trends just happen to coincide, causing them to statistically correlate without either variable having a real causal affect on the other. The citations are real articles. The first citation DOI:10.15585/mmwr.mm6534a4 is on the Center for Disease Control (CDC) web site at [1] and the second citation DOI:10.1016/j.vaccine.2012.05.050 is an article in Vaccine at [2] . Both articles describe the effects of the vaccine for varicella which is the virus that causes chicken pox and shingles (also known as herpes zoster). The title text states that people with all six of the names in the last panel (and indeed, most people in general) tend to think that it's weird we have teeth after thinking about it for a while, but that people named Trevor don't in an unexplained statistical anomaly. Teeth are a normal and near-universal part of the human anatomy (and that of many other animals). Like many aspects of biology, they're generally taken for granted, but can seem "weird" if you think about them too much. Randall has often demonstrated a tendency to over-analyze typical aspects of life until they become troubling. Here, he jokes that people with one particular name (Trevor) don't experience this, for unexplained statistical reasons. This is, of course, fictional. The joke comes from the fact that, were that claim true, it would be as random and as hard to believe as the real phenomenon that the comic addresses. [The first panel shows graph with only the x-axis labeled and with seven labeled ticks. The y-axis has three ticks with percentage labels. A red line rises from bottom to top as it goes from left to right. There is an arrow pointing at the graph with a label. Above the left part of the red line there is a title and beneath that a reference to the source of the data in gray font.] [According to the graph, the percentage is close to 0 for ages below 15 and close to 100 for ages above 30.] Fraction of kids your age who got chicken pox (Very rough US estimates based on DOI:10.15585/mmwr.mm6534a4 and DOI:10.1016/j.vaccine.2012.05.050) 100% 50% 0% Your age: 5  10  15  20  25  30  35 Vaccine introduced in 1995 [The second panel shows a graph with only the x-axis labeled and with seven labeled ticks. The graph has six gray lines with labels on them. To the right is a title and beneath that a reference to the source of the data in gray font.] [According to the graphs, Sarah and Brian are more popular names for older age groups.] Relative popularity of several names in your age group (Source: ssa.gov) Harper Sarah Jaxon Brian Brooklyn Logan Your age: 5  10  15  20  25  30  35 [The third panel shows a list of names with a percentage next to them. Above the list is a title and beneath that a statement in gray font:] Chicken pox incidence by name: (Very rough estimate) Brian: 75% Sarah: 60% Logan: 20% Brooklyn: 10% Jaxon: 4% Harper: 2% [Caption below the panels:] Fun Fact: People named "Sarah" and "Brian" think chicken pox is normal and common, and people named "Logan" and "Harper" do not.

Super Bowl Watch Party

Super Bowl Watch Party

https://www.xkcd.com/1951

https://www.explainxkcd.com/wiki/index.php/1951:_Super_Bowl_Watch_Party

[A woman, looking like Megan, walks up to a group of people watching TV. Cueball and Megan (with shorter hair than the walking woman) are sitting on a couch. A Cueball-like guy sits in front of them, while Ponytail lies on the ground, head resting on a hand, in front of a TV, which is quite far from the couch.] Woman: Morning. How's the game? Cueball: Eagles got to the 26-yard line around midnight. They've been walking across the field since then. Just entered a huddle. Megan: I bet the next frame will be a cut. Guy on floor: You always say that. Ponytail: Do you think the first ads will come by the end of February? [Caption below the comic:] I'm at a year-round Super Bowl watch party. We're playing the stream at 1 / 2300x speed, so it will end just as next year's Super Bowl starts.

The Super Bowl is the annual championship game of the National Football League (NFL), the highest level of professional American football . In late January or early February each year, the winner of the American Football Conference (AFC) plays the winner of the National Football Conference (NFC) to determine the champion. In Super Bowl LII held on Sunday, February 4, (the day before this comic's release), the NFC champion Philadelphia Eagles defeated the AFC champion New England Patriots 41-33. Based on its wide-reaching cultural impact, the Super Bowl is the single most important American football game of the year. Over a hundred million people (across the world) watch it, many of whom are not even fans of American football. Many people have parties centered on watching the game. The full game lasts around four hours, including breaks for advertisements and a halftime. The halftime show of the Superbowl includes a live musical performance, and is generally considered one of the most prestigious shows in the country, meaning it will generally be an elaborate show by a particularly popular artist or group. Because of the high viewership of the Superbowl, advertising time is very expensive ($5 million for a 30-second national spot, as of 2019). This has led to companies putting substantial resources into producing the commercials, to make them as memorable as possible. The net effect is that the halftime show and the commercials, despite being interruptions to the game, have become attractions in their own right, with some viewers tuning in primarily, or even solely, to watch them. Cueball and Megan (on the couch) have such a Super Bowl Watch Party going with their friends (hence the title), but in order to watch the game so that the end will be at the start of the next game, they have slowed down the broadcast so the game takes an entire year to watch. Television in the United States is broadcast at 29.97 frames per second (usually rounded up to 30fps) and takes four hours, for a total of 431568 frames. But by slowing the video down by a factor of 2300, the show would last a full year. (Actually it would last 33,119,967 seconds which is 383 days, 18 days more than a year. To make it last a year, minus 4 hours, it should be slowed down a factor of 2189). Each frame would be shown for about 76.7 seconds. Each day of watching the slow video would cover just under 40 seconds of "actual" time. With this method of viewing, the watchers are instead reduced to analyzing the game frame-by-frame, which may make it easier to understand the sequence of events, but also creates a feeling of tedium. [ citation needed ] Due to this extension creating a lack of variety, Megan tries to make it interesting by guessing the next frame shown will be a cut to a different camera angle. Cuts happen frequently during the broadcast, especially when the ball is not in play, and these cuts may be marked by a black screen. If this is the case, then the cut will be around a minute of nothing to look at at this speed. Megan has a relatively high probability (albeit still incredibly low, with cuts being less than one in every 1000 frames) of being right simply by chance that the next frame will be a cut, but Cueball's tired comment that she always guesses that indicates that the game is so slow or the cuts are so rare that she is almost never correct. Ponytail asks if they think the first ad block will come out before the end of February, about 20 days after the start of the Super Bowl show. The ads and halftime show are considered integral parts of the broadcast, and many advertisers debut elaborate commercials especially for this game, since so many people watch it. Many people claim to watch the Super Bowl only for the commercial breaks, as mentioned in 60: Super Bowl , and the anticipation for these is exaggerated for this game, as the wait is much longer with the extended broadcast. (In exchange, however, the commercials will be longer, too.) The title text refers to how, during a commercial break during the 2018 Super Bowl, only blackness was broadcast for 28 seconds due to equipment failure at NBC. At the rate they watch it would last almost 18 hours as described (17 hours 53 minutes). In previous comics regarding the Super Bowl, Randall has explained that he now watches the Super Bowl ( 1480: Super Bowl ), despite previously expressing a lack of interest in the game ( 60: Super Bowl ) or any other sport ( 1107: Sports Cheat Sheet ). A slowly updating video is similar to the concept behind 1190: Time , and is also reminiscent of Douglas Gordon's 1993 art installation 24 Hour Psycho . Also, As Slow as Possible is an organ piece that is currently played in a German church - it will end in 2640, after 639 years of continuous playing. The theme of a group becoming interested in frame-by-frame shots is reminiscent of 915: Connoisseur . Related to frame-by-frame film watching is the Cinema interruptus concept used by film critic Roger Ebert at the Conference on World Affairs , where you first watch a film at normal speed, without interruptions, and then you watch it again, over several afternoons - while everybody present can stop the film at any time, and have a discussion about anything related to the scene. This is also a method that coaches use to discuss recordings of games. [A woman, looking like Megan, walks up to a group of people watching TV. Cueball and Megan (with shorter hair than the walking woman) are sitting on a couch. A Cueball-like guy sits in front of them, while Ponytail lies on the ground, head resting on a hand, in front of a TV, which is quite far from the couch.] Woman: Morning. How's the game? Cueball: Eagles got to the 26-yard line around midnight. They've been walking across the field since then. Just entered a huddle. Megan: I bet the next frame will be a cut. Guy on floor: You always say that. Ponytail: Do you think the first ads will come by the end of February? [Caption below the comic:] I'm at a year-round Super Bowl watch party. We're playing the stream at 1 / 2300x speed, so it will end just as next year's Super Bowl starts.

Backpack Decisions

Backpack Decisions

https://www.xkcd.com/1952

https://www.explainxkcd.com/wiki/index.php/1952:_Backpack_Decisions

[Cueball stands in front of a store display with 17 backpacks and a couple of boxes on the shelf. He has pulled two backpacks down, and they sit at his feet along with a messenger bag (or satchel) behind him. He thinks to himself:] It's down to two: the one with the charger pocket and the one with— Wait, that other one is waterproof! Ugh. Do I even want a backpack? Maybe I should be looking at messenger bags again. OK, starting over. [Caption below the comic:] Amount of time I’ve spent paralyzed by indecision over choosing the right… [A bar graph is shown. Each label is followed by a black bar representing the amount of time:] College [short bar that is 40 pixels wide] Phone [short bar that is 26 pixels wide] Apartment [short bar that is 33 pixels wide] Car [shortest bar, 20 pixels wide] Laptop [second longest bar, 46 pixels wide] Backpack [longest bar, 202 pixels wide] Previous comics explained that decision paralysis might happen because there are detailed reviews online for the items (in 1036: Reviews ), you have very similar options and unlimited internet access (in 1801: Decision Paralysis ), or just that you're a nerd (in 309: Shopping Teams ).

Cueball , probably representing Randall , is having issues choosing a good backpack. He notices their different features and is indecisive. After presumably spending a long time choosing, he is able to narrow his choices down to two backpacks, only to discover that another backpack had the extra feature of being waterproof, a criterion he had not up to then been accounting for. This has made him more indecisive. Frustrated by the extra information load, he considers giving up on backpacks to take another look at messenger bags. Disregarding that thought, he decides to start over, evaluating all of the backpacks again considering the new information. Clearly he is spending a lot of time on this, and the chart below shows that he spends more time unsure of what backpack to pick than of any other major choice, such as a college or a car. This is unusual, since differences between backpacks impact one's life much less than those between colleges or cars. [ citation needed ] A backpack and its features, or lack thereof, might impact a person on a more ongoing and intimate basis than a college choice (which, for Randall, was a long time ago) or a car (if your view of cars mainly concerns their function) in certain situations. A perfectionist technology geek, such as Cueball or Randall (as Cueball is implied to be) would likely remember, every time he used his backpack, the satisfaction of having found the perfect backpack, or the disappointment of being unable to do so. The title text is Cueball having a conversation (or thinking to himself) about a backpack, which seems (absurdly) to be made of heavy tungsten mesh. In fact, at 85 pounds (39 kg), it is so heavy that Cueball thinks he will need to carry it around in a cart, defeating the purpose of the backpack. However, Cueball considers it simply because of the perfect pocket arrangement, which he cannot use anyway, due to the backpack's heaviness. The explanation about the pocket arrangement is written in all caps , indicating that Cueball is yelling from pure excitement at the pocket arrangement. [Cueball stands in front of a store display with 17 backpacks and a couple of boxes on the shelf. He has pulled two backpacks down, and they sit at his feet along with a messenger bag (or satchel) behind him. He thinks to himself:] It's down to two: the one with the charger pocket and the one with— Wait, that other one is waterproof! Ugh. Do I even want a backpack? Maybe I should be looking at messenger bags again. OK, starting over. [Caption below the comic:] Amount of time I’ve spent paralyzed by indecision over choosing the right… [A bar graph is shown. Each label is followed by a black bar representing the amount of time:] College [short bar that is 40 pixels wide] Phone [short bar that is 26 pixels wide] Apartment [short bar that is 33 pixels wide] Car [shortest bar, 20 pixels wide] Laptop [second longest bar, 46 pixels wide] Backpack [longest bar, 202 pixels wide] Previous comics explained that decision paralysis might happen because there are detailed reviews online for the items (in 1036: Reviews ), you have very similar options and unlimited internet access (in 1801: Decision Paralysis ), or just that you're a nerd (in 309: Shopping Teams ).

The History of Unicode

The History of Unicode

https://www.xkcd.com/1953

https://www.explainxkcd.com/wiki/index.php/1953:_The_History_of_Unicode

[1988:] [A bearded man holds a document labeled "Unicode". Most likely he represents Joe Becker.] Bearded man: My "Unicode" standard should help reduce problems caused by incompatible binary text encodings. [2018:] [A tweet from Twitter is shown. To the left of Senator Angus King's name is his avatar (a face with a mustache) and to the right is the blue checkmark used by Twitter to signify a verified user.] Senator Angus King‏ @SenAngusKing Great news for Maine - we're getting a lobster emoji!!! Thanks to @unicode for recognizing the impact of this critical crustacean, in Maine and across the country. Yours truly, Senator 🐮👑 2/7/18 3:12 PM [Cueball and the bearded man (the latter now grey-haired) are looking at a wall with the Unicode standard, labeled "1988", and Senator King's tweet, labeled "2018", posted on it.] Cueball: What... what happened in those thirty years? Bearded man: Things got a little weird, okay?

An encoding of a character set is a mapping from characters to numbers. For example, the letter "A" might be represented by the value 65. A problem was that each script had its own character set. Different characters could be represented by the same value. Some languages, such as Japanese, had several inconsistent character encodings, so before people could send text, they would have to have agreed which character set to use. Unicode was planned as a way of solving this by providing for a single character encoding for all the various characters used in the world's languages. Unicode is run by a consortium of major technology companies and stakeholders. The founders of Unicode include Joe Becker , who worked for Xerox in the 1980s. He has a beard and may be the character featured in the first and third panels. New characters have continued to be added to Unicode, and recently many " emoji " (picture characters) have been added. Emoji were originally added to be compatible with text message encodings in Japan, but after devices in other countries started supporting them as part of Unicode, they caught on worldwide. Now emoji characters are added for their own sake, not just for compatibility. The lobster emoji , 🦞, was approved as part of Unicode 11, for release in 2018. This comic was published in 10 February 2018‎. This comic shows the creator of Unicode talking about how it would change the way we thought about managing text, which could help with incompatible binary text encoding. This seems to have derailed over the next 30 years, as shown in a real tweet from the junior Senator from Maine , Angus King . In the tweet , Sen. King writes that he is excited that the system is getting a new lobster emoji, showing that now the Unicode system is used for more frivolous reasons. He even signs using two emoji to form his name. There is a cattle breed called Angus cattle , so the cow emoji, 🐮, stands for "Angus", and the crown emoji, 👑, of course represents "King". Thus Angus King becomes 🐮👑. This is thus not part of the xkcd joke; it just uses the real tweet for comic effect. The tweet was released February 7th, only two days before this comic; the second comment on the tweet posted this comic and asked which came first, but of course the tweet did. A user comments that Senator King should see it as a badge of honor (🎖) to have his tweet included in an xkcd strip... The title text imagines that Unicode will gain other unexpected roles in the next 30 years. In particular it acts as an armed force, capable of intervening in military disputes, such as an annexation of Maine by its neighbor, New Hampshire. The title text ends with three Unicode emoji: "🙏" code point 1F64F "PERSON WITH FOLDED HANDS", "🚁" code point 1F681 "HELICOPTER", and "🎖" code point 1F396 "MILITARY MEDAL", suggesting that they are thanking them for their effort in the war, sending helicopters and soldiers to aid them against New Hampshire. The phrase "we're once again an independent state" may also be a political pun, as 2048 should be an election year, and King is an Independent senator. [1988:] [A bearded man holds a document labeled "Unicode". Most likely he represents Joe Becker.] Bearded man: My "Unicode" standard should help reduce problems caused by incompatible binary text encodings. [2018:] [A tweet from Twitter is shown. To the left of Senator Angus King's name is his avatar (a face with a mustache) and to the right is the blue checkmark used by Twitter to signify a verified user.] Senator Angus King‏ @SenAngusKing Great news for Maine - we're getting a lobster emoji!!! Thanks to @unicode for recognizing the impact of this critical crustacean, in Maine and across the country. Yours truly, Senator 🐮👑 2/7/18 3:12 PM [Cueball and the bearded man (the latter now grey-haired) are looking at a wall with the Unicode standard, labeled "1988", and Senator King's tweet, labeled "2018", posted on it.] Cueball: What... what happened in those thirty years? Bearded man: Things got a little weird, okay?

Impostor Syndrome

Impostor Syndrome

https://www.xkcd.com/1954

https://www.explainxkcd.com/wiki/index.php/1954:_Impostor_Syndrome

[Megan points at Ponytail and introduces her to Cueball.] Megan: This is Dr. Adams. She's a social psychologist and the world's top expert on impostor syndrome. Dr. Adams: Haha, don't be silly! There are lots of scholars who have made more significant… Dr. Adams: …Oh my God.

Impostor syndrome is a common psychological phenomenon where successful individuals are unable to internalize their success and fear being exposed as a "fraud" or "impostor." Events and accomplishments that would seem to be evidence of competence, skill, intelligence, and so forth, are instead viewed (by the person) as luck, timing, and the ability to appear more confident/competent than they actually are. Ponytail , representing Dr. Adams, is introduced by Megan as "the world's top expert on impostor syndrome." Dr. Adams then demonstrates that she herself (like a relatively large number of women according to some reports [1] ) is afflicted by this syndrome. She realizes this after she reacts to the flattering introduction by starting about "other scholars" whom she deems to be superior to her. The Dunning–Kruger effect , mentioned in the title text, is a cognitive bias wherein people who possess comparatively little direct expertise in a given field may unrealistically inflate their estimation of their own level of expertise in that field; while those who actually are highly competent (and especially experts on the topic at hand) are likely to downplay their level of expertise. This cognitive bias arises when people of low relevant ability lack the practical knowledge to validly assess their competence: The criteria for good or poor performance in a given field may not be weighed accurately by someone lacking direct expertise and formal training in that specific field. For instance, a commuter experienced in filtering through traffic quickly may consider themselves to be excellent at driving, while a professional evaluating driving habits may observe adherence to regulations and best practices for safety to be the primary criteria for being a "good" driver. Conversely, people with extensive knowledge of a given field may develop an acute awareness of the necessarily limited scope of their (or any one person's) expertise. While this effect primarily refers to cognitive ability, it is also sometimes used to refer to people who are competent in one area (and thus not lacking metacognitive skills) believing that their abilities grant them unusually-high aptitude in a different but seemingly related area. In practice, more expertise still largely correlates to higher confidence in one's expertise (that is to say that competence remains positively correlated with an individual's perception of their own competence), but a lack of the appropriate cognitive skills can result in that perception of competence starting at a high level yet increasing at a slower rate. However, in popular usage, the Dunning–Kruger effect is used to claim that a negative correlation exists, and that non-experts will claim expertise and confidence at a higher overall level than actual experts. In the title text, a conference for the Dunning–Kruger effect was having trouble, presumably because the actual researchers were downplaying their knowledge and expertise to the point where they refused to be the keynote speaker, while the random undergrads (who lack experience in the topic) felt sufficiently confident in their knowledge of it to give the keynote. This more closely matches both the secondary usage (as undergrads are unlikely to lack metacognitive skills, but may inflate their understanding) and the popular usage (as the confidence is inverse to the actual competence) than the primary and in-practice observance made in the original research. [Megan points at Ponytail and introduces her to Cueball.] Megan: This is Dr. Adams. She's a social psychologist and the world's top expert on impostor syndrome. Dr. Adams: Haha, don't be silly! There are lots of scholars who have made more significant… Dr. Adams: …Oh my God.

Robots

Robots

https://www.xkcd.com/1955

https://www.explainxkcd.com/wiki/index.php/1955:_Robots

[Cueball is sitting at his desk in an office chair pointing to his laptop while looking back over his shoulder talking to Megan off-panel.] Cueball: Did you see this Boston Dynamics robot video? Cueball: We're definitely all gonna die. [Megan walks in to the panel towards Cueball who still looks at her, but stops pointing.] Megan: You know, it's funny. Megan: Humans see a robot open a door, and we all instantly assume we're in mortal peril. [Zoom in on the heads of Megan and Cueball, both now looking at the off-panel screen.] Megan: So doesn't it make more sense to say the robots are all gonna die? Cueball: Violently overreacting to a perceived threat? That doesn't sound like humans. Megan: Yeah, I must be thinking of some other species. Possibly coincidentally, approximately seven weeks before this video and strip, the series " Black Mirror " released an episode entitled " Metalhead ". The episode set in a post-apocalyptic world where humans are hunted by robots highly reminiscent of this line of Boston Dynamics robots. Clearly, the concept of these robots becoming a threat isn't unique to XKCD.

This comic refers to a YouTube video posted one day earlier by robotics company Boston Dynamics . The video shows a quadruped robot with a roughly canine form approach a door, then stop and 'look' to the side where a second robot appears, which has an articulated arm attachment on top. This robot sizes up the door, then uses its arm to grasp the handle and open the door. It holds the door open for the first robot, then follows it through the doorway. The video was extremely popular, receiving over four million views in the first day. Many social media comments joked that humanity is doomed, as the robots we are developing will soon become capable enough to rise up and overthrow us. This is a common jest or anxiety expressed when robots manage to master a task that previously had given them difficulty. It is especially appropriate here, since the ability to open doors is extremely useful when dealing with humans. Randall has previously made the point that a robot uprising would promptly fail because most robots couldn't successfully open doors (or even successfully negotiate thresholds, in some cases). This latest advance seems to specifically undercut that assurance. After Cueball sees this video, he reiterates the same line by saying that we're definitely going to die. Megan , however, offers an alternative view: that in fact, due to human nature, it is the robots that are in mortal peril from this technological development, not humans, since humans tend to respond aggressively to potential threats. Taking Megan's point, Cueball sarcastically suggests that humans don't tend to overreact violently to perceived threats, to which Megan replies, equally sarcastically, that she must be thinking of another species. The title text may refer to the Mad Scientist or Evil Genius tropes in science fiction, where someone builds an army of robots with the intent of using them to take over the world. Alternatively, the title text could refer to the real life phenomena of military programs expending enormous resources to develop unmanned offensive capabilities, such as the Predator drone and SWORDS mobile weapon platform . In the latter context, it may be sensible to show concern with the methods, reasoning, motivations, and long-term stability of people directing the development of potentially lethal robots. Boston Dynamics is one of the foremost innovators in the field of military-grade automation. [Cueball is sitting at his desk in an office chair pointing to his laptop while looking back over his shoulder talking to Megan off-panel.] Cueball: Did you see this Boston Dynamics robot video? Cueball: We're definitely all gonna die. [Megan walks in to the panel towards Cueball who still looks at her, but stops pointing.] Megan: You know, it's funny. Megan: Humans see a robot open a door, and we all instantly assume we're in mortal peril. [Zoom in on the heads of Megan and Cueball, both now looking at the off-panel screen.] Megan: So doesn't it make more sense to say the robots are all gonna die? Cueball: Violently overreacting to a perceived threat? That doesn't sound like humans. Megan: Yeah, I must be thinking of some other species. Possibly coincidentally, approximately seven weeks before this video and strip, the series " Black Mirror " released an episode entitled " Metalhead ". The episode set in a post-apocalyptic world where humans are hunted by robots highly reminiscent of this line of Boston Dynamics robots. Clearly, the concept of these robots becoming a threat isn't unique to XKCD.

Unification

Unification

https://www.xkcd.com/1956

https://www.explainxkcd.com/wiki/index.php/1956:_Unification

[Ten rounded frames with text inside are shown in two rows. Below each frame there is a line going down and then this line either joins with one or two of the other frames lines or in two cases do not joins with any other. At the bottom of the panel the now five remaining lines turn towards the center of the bottom of the panel and ends in arrows that points towards three question marks. The first three frames' lines are unified, same goes for the next two, and the three after that. The lines of the last two are not joined with any other lines. The text in the transcript is given as it appears from left to right, disregarding if it is the top or bottom row, but this will alternate through the ten frames, starting with one up, then one down etc.] [Group one, starting with up:] Electricity Magnetism Weak force [Group two starting with down:] East Germany West Germany [Group three starting with down:] Star Wars Disney Pixar [Two single frames, the first is up:] Strong force Gravity [All five arrows points to this:] ??? [Caption below the panel:] Progress toward unifying the fundamental forces of nature

In physics, the fundamental interactions, also known as fundamental forces, are the interactions that do not appear to be reducible to more basic interactions. There are four fundamental interactions known to exist: the gravitational and electromagnetic interactions, which produce significant long-range forces whose effects can be seen directly in everyday life, and the strong and weak interactions, which produce forces at minuscule, subatomic distances and govern nuclear interactions. Some scientists speculate that a fifth force might exist, but, if so, it is not widely accepted nor proven. This comic lists five physical forces (it split up electricity and magnetism), but also includes a number of other things (two countries and three businesses) that are known for "unifying" in a non-physics sense. East and West Germany united politically in 1990 , more than forty years after being divided at the end of World War II . Entertainment company Disney has united in a business sense with a number of others over the years; the comic mentions animation studio Pixar and the Star Wars franchise. The comic states that this is the progress toward unifying the fundamental forces of nature, which is absurd, with the addition of Disney and Germany , neither of which is one of the fundamental forces. [ citation needed ] Star Wars is, of course, all about The Force , but this has, for some reason, gone unnoticed by most physicists. The title text jokes that some physicists tried to unify the force of gravity with the 2013 movie Gravity , starring Sandra Bullock . Of course, this is also absurd, but it turns out that this is just another jab by Randall at George Lucas for selling his rights to Star Wars to Disney . The jab comes when he makes it clear that the director of Gravity Alfonso Cuarón would refuse to sell the rights to his film to Disney, even if he was held in underground chamber of water for 10 31 years. This water chamber and incredible time span is a reference to Proton decay , which is being investigated by trying to detect the Cherenkov radiation that could occur from possible decay of protons in water. These measurements are being conducted in immense water tanks buried under mountains to protect them against similar signals that could result from cosmic radiation. The same type of tanks have been used to detect neutrinos . The half life of protons is currently believed to be between 10 31 –10 36 years. This should be compared to the age of the universe at around 1.3×10 10 years, which means that one second compared to the age of the universe is larger than the age of the universe compared to the smallest suggested half life of the proton (as used in the comic) by a factor of about 10,000, but even this time would not make Cuarón cave in... [Ten rounded frames with text inside are shown in two rows. Below each frame there is a line going down and then this line either joins with one or two of the other frames lines or in two cases do not joins with any other. At the bottom of the panel the now five remaining lines turn towards the center of the bottom of the panel and ends in arrows that points towards three question marks. The first three frames' lines are unified, same goes for the next two, and the three after that. The lines of the last two are not joined with any other lines. The text in the transcript is given as it appears from left to right, disregarding if it is the top or bottom row, but this will alternate through the ten frames, starting with one up, then one down etc.] [Group one, starting with up:] Electricity Magnetism Weak force [Group two starting with down:] East Germany West Germany [Group three starting with down:] Star Wars Disney Pixar [Two single frames, the first is up:] Strong force Gravity [All five arrows points to this:] ??? [Caption below the panel:] Progress toward unifying the fundamental forces of nature

2018 CVE List

2018 CVE List

https://www.xkcd.com/1957

https://www.explainxkcd.com/wiki/index.php/1957:_2018_CVE_List

[A heading is centered above a list of 21 vulnerabilities] Leaked list of major 2018 security vulnerabilities CVE-2018-????? Apple products crash when displaying certain Telugu or Bengali letter combinations. CVE-2018-????? An attacker can use a timing attack to extploit a race condition in garbage collection to extract a limited number of bits from the Wikipedia article on Claude Shannon. CVE-2018-????? At the cafe on Third Street, the Post-it note with the WiFi password is visible from the sidewalk. CVE-2018-????? A remote attacker can inject arbitrary text into public-facing pages via the comments box. CVE-2018-????? MySQL server 5.5.45 secretly runs two parallel databases for people who say "S-Q-L" and "sequel." CVE-2018-????? A flaw in some x86 CPUs could allow a root user to de-escalate to normal account privileges. CVE-2018-????? Apple products catch fire when displaying emoji with diacritics. CVE-2018-????? An oversight in the rules allows a dog to join a basketball team. CVE-2018-????? Haskell isn't side-effect-free after all; the effects are all just concentrated in this one. computer in Missouri that no one's checked on in a while. CVE-2018-????? Nobody really knows how hypervisors work. CVE-2018-????? Critical: Under Linux 3.14.8 on System/390 in a UTC+14 time zone, a local user could potentially use a buffer overflow to change another user's default system clock from 12-hour to 24-hour. CVE-2018-????? x86 has way too many instructions. CVE-2018-????? NumPy 1.8.0 can factor primes in O (log n ) time and must be quietly deprecated before anyone notices. CVE-2018-????? Apple products grant remote access if you send them words that break the "I before E" rule. CVE-2018-????? Skylake x86 chips can be pried from their sockets using certain flathead screwdrivers. CVE-2018-????? Apparently Linus Torvalds can be bribed pretty easily. CVE-2018-????? An attacker can execute malicious code on their own machine and no one can stop them. CVE-2018-????? Apple products execute any code printed over a photo of a dog with a saddle and a baby riding it. CVE-2018-????? Under rare circumstances, a flaw in some versions of Windows could allow Flash to be installed. CVE-2018-????? Turns out the cloud is just other people's computers. CVE-2018-????? A flaw in Mitre's CVE database allows arbitrary code insertion. [~~Click here for cheap viagra~~] Randall has previously referenced diacritics in 1647: Diacritics . Bruce Schneier was previously mentioned in the title texts of 748: Worst-Case Scenario and 1039: RuBisCO .

CVE (Common Vulnerabilities and Exposures) is a standardized format for assigning an identity to a cybersecurity vulnerability (similar to the way that astronomical bodies are assigned unique identifiers by committees). Giving vulnerabilities a unique identifier makes them easier to talk about and helps in keeping track of the progress made toward resolving them. The typical format of a CVE identifier is CVE-[YEAR]-[NUMBER] . For example, the CVE identifier for 2017's widespread Meltdown vulnerability is CVE-2017-5754 . CVEs also contain a short description of the issue. In this comic (released in February 2018), Randall presents a number of spurious predicted CVEs for later in 2018. Each CVE identifier is given as "CVE-2018-?????", reflecting the fact that they have not yet happened so we don't know exactly what their CVE identifier will be. Following are short descriptions of all the vulnerabilities mentioned in the comic. Apple products crash when displaying certain Telugu or Bengali letter combinations. This refers to a real vulnerability in iOS and MacOS publicized a few days before the comic was released, as well as past similar iOS vulnerabilities. An attacker can use a timing attack to extploit [ sic ] a race condition in garbage collection to extract a limited number of bits from the Wikipedia article on Claude Shannon. The reference to using a Timing Attack to exploit a race condition in garbage collection refers to Meltdown and Spectre CPU flaws that can be exploited in a cloud server like the ones in Wikipedia. Claude Shannon was an early and highly influential information scientist whose work underlies compression, encryption, security, and the theory behind how information is encoded into binary digits. This is not a security problem, since Wikipedia articles are public. However, since Shannon formulated how the amount of unique or actual information some entity contains is proportional to the number of bits required to encode it, retrieving only a few bits casts a dark perspective upon the significance of the Shannon article's content. At the cafe on Third Street, the Post-it note with the WiFi password is visible from the sidewalk. Cafés often offer free access to WiFi as a service to patrons, as a business strategy to encourage said patrons to remain in the building and buy more coffee. Some use a password, so that only patrons can use the WiFi, and may display the password on signage inside. Since anybody could go into the cafe to read the post-it, and then use the network from nearby, the ability to read it from outside is, at most, a trivial problem. For systems that are supposed to be secure, writing passwords in a visible place is a major security flaw. For instance, following the 2018 Hawaii false missile alert , the agency concerned received criticism for a press photo showing a password written on a sticky note attached to a monitor. A remote attacker can inject arbitrary text into public-facing pages via the comments box. Describes a common feature on news sites or social media sites like Facebook. The possibility for users to "inject" text into the page is by design. This is a humorous reference to the relatively common security vulnerability " persistent cross-site scripting ", where input provided by a user, such as through a comment section, can result in dangerous content containing arbitrary HTML or JavaScript code being displayed to other users. MySQL server 5.5.45 secretly runs two parallel databases for people who say "S-Q-L" and "sequel." Some people pronounce " SQL " like "sequel", after SQL's predecessor "SEQUEL (Structured English Query Language)". The standard for SQL suggests that it should be pronounced as separate letters; however, the author of SQL pronounces it "sequel", so the debate persists (with even more justification than arguments about how to pronounce "GIF"). MySQL is an open-source relational database management system. The latest generally available version (at the time of writing) is MySQL 5.7. A flaw in some x86 CPUs could allow a root user to de-escalate to normal account privileges. Privilege escalation refers to any illegitimate means by which a system user gains greater access privileges than they are supposed to have. The most highly-sought privilege is that of the root user, which allows complete access to an entire system— a superuser . Any flaw that would allow an ordinary user to escalate to superuser status is a critical security threat, as they then have full control of the machine. This is what most hackers seek to achieve when attacking a device. This CVE presents the less-threatening reverse situation: allowing a root user to de-escalate to normal account privileges. In fact, root users can already do this at any time; superuser privileges allow them to take control of any user account, so they can simply switch to an account which has fewer privileges than the root user. Apple products catch fire when displaying emoji with diacritics. This is a reference to a common problem of modern gadgets catching fire (usually related to flaws in lithium-ion batteries), as well as to Apple products crashing when attempting to display certain character sequences. Diacritics are the accents found on letters in some languages (eg. č, ģ ķ, ļ, ņ, š, ž). These would not normally be found on emojis [ citation needed ] . 🔥̃ is an example of such an emoji. An oversight in the rules allows a dog to join a basketball team. This probably refers to the movie Air Bud , about a dog playing basketball. This has been a common theme in xkcd comics: see 115: Meerkat , 1439: Rack Unit , 1819: Sweet 16 , 1552: Rulebook . In 2017, it was discovered that an oversight in the constitution of the state of Kansas may permit a dog to be governor . Shortly before this comic published, the Secretary of State's office ruled that it could not . Haskell isn't side-effect-free after all; the effects are all just concentrated in this one computer in Missouri that no one's checked on in a while. Haskell is a functional programming language. Functional programming is characterized by using functions that don't have side effects because they can not change things accessible in other parts of the program, as in 1312: Haskell . The joke here is discovering that it does indeed have side-effects, manifested via external alteration, not violating the internal alteration paradigm. It may also be a reference to " The Ones Who Walk Away From Omelas ," a short story by Ursula Le Guin in which a utopian city concentrates all its misery into one child who is locked away in a basement. Nobody really knows how hypervisors work. "Hypervisors" are a tool for computer virtualization. Virtualization is implemented via various combinations of hardware and/or software, which requires a computer to completely simulate another computer, with its own unique hardware and software, and to varying degrees as to whether or not the virtualization is aware of or can determine whether it is being virtualized. Many IT professionals and businesses rely heavily on various forms of virtualization, but most of the individual employees would be hard-pressed to explain how it works. Programs running on other virtual computers, or on the real computer, may be able to access information on a virtual computer in ways which would not be possible with a single real computer. Consequently, understanding how the hypervisor works is important to assessing the security of a virtual server. Meltdown and Spectre are related to this. Critical: Under Linux 3.14.8 on System/390 in a UTC+14 time zone, a local user could potentially use a buffer overflow to change another user's default system clock from 12-hour to 24-hour. This joke is about arcane systems that are running Linux in exceedingly rare situations, meaning that reproducing errors would be incredibly difficult or inconvenient, and would only affect a very tiny user base (if any at all). System/390 is an IBM mainframe introduced almost 30 years before this comic, which has a version of Linux. UTC+14 is a time zone used only on some islands in the Pacific Ocean (Primarily the Line Islands ) and is also the earliest time zone on Earth. Even if all of these absurd conditions were met, the resulting vulnerability would still be relatively benign: simply changing a user's preferred clock display format. Other xkcd comics make references to such obscure computer-time issues relating to time zones and time conversions, and how many programmers find these issues frustrating or even traumatizing. x86 has way too many instructions. The x86 architecture (used in many Intel and AMD processors) is very complicated. Processors typically implement such a complex architecture using programs (microcode) run on a set of hidden, proprietary processors. The details of these hidden machines and errors in the microcode can result in security vulnerabilities, such as Meltdown, where the physical machine does not match the conceptual machine. A more complicated instruction set is more complex to implement. [ citation needed ] The x86 architecture is considered "CISC" (a " Complex instruction set computer "), having many instructions originally provided to make programming by a human simpler; other examples include the 68000 series used in the first Apple Macintosh . In the 1980s, this design philosophy was countered by the "RISC" (" Reduced instruction set computer ") design movement - based on the observation that computer programs were increasingly generated by compilers (which only used a few instructions) rather than directly by people, and that the chip area dedicated to extra instructions could be better dedicated to, for example, cache. Examples of RISC style designs include SPARC , MIPS , PowerPC (used by Apple in later Macintoshes) and the ARM chips common in mobile phones. Historically, there was considerable discussion about the merits of each approach. At one time the Mac and Windows PC were on different sides; owners of other competing systems such as the Archimedes and Amiga had similar arguments on usenet in the early 1990s. This "issue" may be posted by someone who still recalls these debates. Technically, the extra instructions do slightly complicate the task of validating correct chip behaviour and complicate the tool chains that manage software, which could be seen as a minor security risk. However, the 64-bit architecture introduced by AMD , and since adopted by Intel , does rationalize things somewhat, and all recent x86 chips break down instructions into RISC-like micro-operations, so the complication from a hardware perspective is localized. Recent security issues, such as the speculative cache load issue in Meltdown and Spectre, depend more on details of implementation, rather than instruction set, and have been exhibited both by x86 (CISC) and ARM (RISC) processors. NumPy 1.8.0 can factor primes in O (log n ) time and must be quietly deprecated before anyone notices. Fantastically, this would be an unimaginable software threat, not to be confused with the even speedier, but future-bound, threat in hardware via Quantum computing . NumPy is the fundamental package for scientific computing with the programming language Python. O (log n ) is Big O notation meaning that the time it takes for a computer algorithm to run is in the order of log n , for an input of size n . O (log n ) is very fast and is more usual for a search algorithm. Prime factorization currently is O ( 2 n n)). If something can find the prime factors of a number this quickly, especially a semiprime with two large factors, it will enable attacks to break many crypto functions used in internet security. However, prime numbers have only a single factor, and "factoring primes" quickly is a simpler problem, that of proving that a number is in fact a prime . Apple products grant remote access if you send them words that break the "I before E" rule. Another joke on the first CVE and a common English writing rule of thumb , which fails almost as often as it succeeds. Possibly a jab at Apple's image, portraying their software as unable to handle improper grammar or spelling. Skylake x86 chips can be pried from their sockets using certain flathead screwdrivers. Skylake x86 chips are a line of microprocessors made by Intel. Some processors are soldered directly to a system board or daughter board, while others are attached to boards that plug into the system board by means of a socket (pins or connectors that make physical contact with receptacles or connectors on a system board). Some sockets, especially older ones, require force to insert or remove, and often require the use of a flat blade screwdriver or a specialized tool, but most modern ones use ZIF (Zero Insertion Force) techniques, often involving a lever or similar to tighten or loosen the friction/tightness of the contacts. No screwdriver is needed in this case. However, any processor can be forcefully removed from its socket with a screwdriver. [ citation needed ] Apparently Linus Torvalds can be bribed pretty easily. Linus Torvalds is the benevolent dictator for life of the Linux kernel codebase. Normally it is hard to make changes because he has the last word, and because the kernel is replicated in all Linux installations. Linus made the news in January 2018 when, having looked at one of Intel's proposed fixes for the Spectre and Meltdown vulnerabilities, he declared " the patches are COMPLETE AND UTTER GARBAGE ". Presumably, it may be found that he may be successfully bribed to be less blunt and/or less critical of vulnerability fixes that are complete and/or utter garbage. If this were the case, this would be a severe critical vulnerability to all Linux servers and machines. An attacker can execute malicious code on their own machine and no one can stop them. The point of an attack is to make someone else's machine perform actions against the owner's will. Anyone can make their own machine execute any code if they have root access and the necessary tools, but this would usually not be described as an attack, except in the case of a locked-down appliance, such as a video game console, a John Deere tractor, or pay TV decoder. Apple products execute any code printed over a photo of a dog with a saddle and a baby riding it. This could refer to a CVE vulnerability of JPG files where JavaScript embedded within the image file is executed by some application. In this case, though, the code is visible on the image instead of invisibly encoded within the image file. The code is also only executed if the image contains a photo of a baby in a saddle riding a dog. It's unclear whether the photo would be a digital photo, a printed photo (i.e. as taken using a digital camera), or maybe both. Other than by some metadata , either internal to the image file, or embedded along with it, as in a web page, or a PDF or other container file, this "bug" would require the device to figure out specifically what the photo contains image-wise (something that's REALLY HARD for computers to do reliably), but would also require OCR (optical character recognition) code to convert the text superimposed on the photo into executable code. In other words, it's hard to believe in 2018 that such a bug could exist. Maybe in the future when such things are more routine...? As an example, OCR used to be hard to do reliably, but now it's a lot more routine and built into a lot of devices. Under rare circumstances, a flaw in some versions of Windows could allow Flash to be installed. Adobe Flash has been an integral browser plugin for decades, but has fallen out of favor in the 2010s, and eventually discontinued because of its notoriously abysmal security record. All security experts advise against installing it. Preventing installation of Flash would make systems more secure, but most versions of Windows do not prevent Flash installation (provided, as of 2021, the user still has a copy of the files with which to do so). The joke here relates to the difficulty of keeping Flash up to date, or even installed properly to begin with. A common user experience, which is the subject of numerous jokes and memes, is the constant nagging notification to install or update Flash in order for web pages to display properly. Many IT professionals will bemoan the trouble they have experienced in the workplace due to these notifications and problems related to them. In late 2020, Microsoft released an optional Windows update that removes Flash and prevents users from installing it again. Turns out the cloud is just other people's computers. This refers to a meme that demands that "cloud" be replaced with "other people's computers" in all marketing presentation to CEOs and non-computer literate persons evaluating the security impact of using cloud services. Part of the humor here is that "the cloud" is, in actuality, simply a term for hosted services, or in other words computers being run by other people (typically businesses that specialize in this type of " Platform as a Service " or "PaaS" service model). Referring to "the cloud" as "other people's computers" is, at its core, entirely accurate, though it takes away the business jargon and simplifies the situation in such a way that it might cast doubt on the security, reliability, and general effectiveness of using "cloud" solutions. In 908: The Cloud , it turns out that Black Hat is the "other people" whose computer is the Cloud. A flaw in Mitre's CVE database allows arbitrary code insertion. [~~CLICK HERE FOR CHEAP VIAGRA~~] Mitre's CVE database is where all CVEs are stored. This log message forms the punchline of the comic, as it implies that all of the exaggerated error messages above might have been inserted by hackers exploiting the vulnerability. To pour salt in the wound, they then included in a typical spam link purporting to offer inexpensive brand-name Sildenafil . It turns out Bruce Schneier is just two mischevious kids in a trenchcoat. Appears in the title text. Bruce Schneier is security researcher and blogger. The "two kids in a trenchcoat" is a reference to the Totem Pole Trench trope. Shortly before this comic was posted, a story went viral in which two kids were photographed attempting this for real to get into a screening of Black Panther . [A heading is centered above a list of 21 vulnerabilities] Leaked list of major 2018 security vulnerabilities CVE-2018-????? Apple products crash when displaying certain Telugu or Bengali letter combinations. CVE-2018-????? An attacker can use a timing attack to extploit a race condition in garbage collection to extract a limited number of bits from the Wikipedia article on Claude Shannon. CVE-2018-????? At the cafe on Third Street, the Post-it note with the WiFi password is visible from the sidewalk. CVE-2018-????? A remote attacker can inject arbitrary text into public-facing pages via the comments box. CVE-2018-????? MySQL server 5.5.45 secretly runs two parallel databases for people who say "S-Q-L" and "sequel." CVE-2018-????? A flaw in some x86 CPUs could allow a root user to de-escalate to normal account privileges. CVE-2018-????? Apple products catch fire when displaying emoji with diacritics. CVE-2018-????? An oversight in the rules allows a dog to join a basketball team. CVE-2018-????? Haskell isn't side-effect-free after all; the effects are all just concentrated in this one. computer in Missouri that no one's checked on in a while. CVE-2018-????? Nobody really knows how hypervisors work. CVE-2018-????? Critical: Under Linux 3.14.8 on System/390 in a UTC+14 time zone, a local user could potentially use a buffer overflow to change another user's default system clock from 12-hour to 24-hour. CVE-2018-????? x86 has way too many instructions. CVE-2018-????? NumPy 1.8.0 can factor primes in O (log n ) time and must be quietly deprecated before anyone notices. CVE-2018-????? Apple products grant remote access if you send them words that break the "I before E" rule. CVE-2018-????? Skylake x86 chips can be pried from their sockets using certain flathead screwdrivers. CVE-2018-????? Apparently Linus Torvalds can be bribed pretty easily. CVE-2018-????? An attacker can execute malicious code on their own machine and no one can stop them. CVE-2018-????? Apple products execute any code printed over a photo of a dog with a saddle and a baby riding it. CVE-2018-????? Under rare circumstances, a flaw in some versions of Windows could allow Flash to be installed. CVE-2018-????? Turns out the cloud is just other people's computers. CVE-2018-????? A flaw in Mitre's CVE database allows arbitrary code insertion. [~~Click here for cheap viagra~~] Randall has previously referenced diacritics in 1647: Diacritics . Bruce Schneier was previously mentioned in the title texts of 748: Worst-Case Scenario and 1039: RuBisCO .

Self-Driving Issues

Self-Driving Issues

https://www.xkcd.com/1958

https://www.explainxkcd.com/wiki/index.php/1958:_Self-Driving_Issues

[Cueball is speaking while standing alone in a slim panel.] Cueball: I worry about self-driving car safety features. [In a frame-less panel it turns out that Cueball is standing between White Hat and Megan, holding his arms out towards each of them, while he continues to speak.] Cueball: What's to stop someone from painting fake lines on the road, or dropping a cutout of a pedestrian onto a highway, to make cars swerve and crash? [Zoom in on Cueball's head as he continues to contemplate the situation holding a hand to his chin, while looking in White Hat's direction. Megan replies from off-panel behind him.] Cueball: Except... those things would also work on human drivers. What's stopping people now? Megan (off-panel): Yeah, causing car crashes isn't hard. [Zoom back out to show all three of them again.] White Hat: I guess it's just that most people aren't murderers? Cueball: Oh, right. I always forget. Megan: An underappreciated component of our road safety system. The title text was published with a typo: "murderers" was misspelled as "muderers." The theme of human fear and overreaction to the advent of more or less autonomous robots also features in 1955: Robots . Self-driving cars is a recurring subject on xkcd. A variation on the idea that humans are mentally "buggy" is suggested in 258: Conspiracy Theories , though in that case divine intervention is requested to implement the "firmware upgrade". This comic appeared one day after the Electronic Frontier Foundation co-released a report titled The Malicious Use of Artificial Intelligence: Forecasting, Prevention, and Mitigation . The report cites subversions and mitigations of AI such as ones used in self-driving cars. However, the report tends toward overly technical means of subversion. Randall spoofs the tenor of the report through his mundane subversions and over-the-top mitigations.

Cueball explains being worried about self-driving cars , noting that it may be possible to fool the sensory systems of the vehicles. This is a common concern with AIs ; since they think analytically and have little to no capability for abstract thought, they can be fooled by things a human would immediately realize is deceptive. However, Cueball quickly assumes that his argument actually doesn't hold up when comparing AI drivers to human drivers, as both rely on the same guidance framework. Human drivers follow signs and road markings, and must obey the laws of the road just as an AI must. Therefore, an attack on the road infrastructure could impact both AIs and humans. However, humans and AIs are not equally vulnerable. For example, a fake sign or a fake child could appear to a human as an obvious fake but fool an AI. A creative attacker could put up a sign with CAPTCHA-like text that would be readable by humans but not by an AI. Cueball further wonders why, in this case, nobody tries to fool human drivers as they might try to fool an AI, but White Hat and Megan point out that most road safety systems benefit from humans not actively trying to maliciously sabotage them simply to cause accidents. [ citation needed ] The title text continues the line of reasoning, noting that if most people did suddenly become murderers, the AI might be needed to be upgraded in order to deal with the presumable increase in people trying to cause car crashes by fooling the AI - a somewhat narrowly-focused solution given that a world full of murderers would probably have many more problems than that. As Megan sees humans as a 'component' of the road safety system, it might also be suggesting a firmware update for the buggy people who have all become murderers, one that would fix their murderous ways. We are not currently at a point where we can create and apply instantaneous firmware updates for large populations; even combining all the behavioral modification tools at our disposal -- psychiatry , cognitive behavioral therapy , hypnosis , mind-altering drugs , prison , CRISPR , etc. -- is not enough to perform such a massive undertaking, as far as we know. The update might be about the car's firmware since it can used to disable the brakes and thus causing or preventing many deaths. [Cueball is speaking while standing alone in a slim panel.] Cueball: I worry about self-driving car safety features. [In a frame-less panel it turns out that Cueball is standing between White Hat and Megan, holding his arms out towards each of them, while he continues to speak.] Cueball: What's to stop someone from painting fake lines on the road, or dropping a cutout of a pedestrian onto a highway, to make cars swerve and crash? [Zoom in on Cueball's head as he continues to contemplate the situation holding a hand to his chin, while looking in White Hat's direction. Megan replies from off-panel behind him.] Cueball: Except... those things would also work on human drivers. What's stopping people now? Megan (off-panel): Yeah, causing car crashes isn't hard. [Zoom back out to show all three of them again.] White Hat: I guess it's just that most people aren't murderers? Cueball: Oh, right. I always forget. Megan: An underappreciated component of our road safety system. The title text was published with a typo: "murderers" was misspelled as "muderers." The theme of human fear and overreaction to the advent of more or less autonomous robots also features in 1955: Robots . Self-driving cars is a recurring subject on xkcd. A variation on the idea that humans are mentally "buggy" is suggested in 258: Conspiracy Theories , though in that case divine intervention is requested to implement the "firmware upgrade". This comic appeared one day after the Electronic Frontier Foundation co-released a report titled The Malicious Use of Artificial Intelligence: Forecasting, Prevention, and Mitigation . The report cites subversions and mitigations of AI such as ones used in self-driving cars. However, the report tends toward overly technical means of subversion. Randall spoofs the tenor of the report through his mundane subversions and over-the-top mitigations.

The Simpsons

The Simpsons

https://www.xkcd.com/1959

https://www.explainxkcd.com/wiki/index.php/1959:_The_Simpsons

[A black frame containing a gray table of two columns and three rows. Most of the text is also gray. The columns and rows have titles. A black jellybean-shaped loop is visually grouping three entries together, the top two in the right column with the bottom left entry. The text in those three boxes are black. Above the table there is a heading:] Fun Fact: 1990 2018 Lisa 8 36 Bart 10 38 Homer & Marge 36-ish 64-ish [Caption below the panel:] If you were Bart and Lisa's age during the first few seasons of The Simpsons, this year you're the same age as Homer and Marge. This is another entry in xkcd's genre of comics that emphasize how surprising the passage of time can be. This was the second Fun fact comic in three weeks, following 1950: Chicken Pox and Name Statistics , after more than two years break from the series. It seems that Randall returned to his old themes this month.

This is another comic with one of Randall's fun facts . The Simpsons is an American animated sitcom centered on the lives of the fictitious Simpson family . It is a very long-running series, having started with a Christmas episode in 1989, with the rest of the first season airing in 1990. As of the publication of this strip, it is still in production, having been on the air for 28 years with the same characters and primary cast. The decision was made early in the series that the characters wouldn't age, meaning that the parents, Homer and Marge , remained perpetually in their mid-thirties. The three children, Bart , Lisa , and Maggie , have remained 10, 8, and 1 year old, respectively. One of the interesting impacts of this dynamic is that the audience and the world have significantly aged over the course of the show, but the characters remain the same age. A rather dramatic example is that many of the early fans were similar in age to the children, but have now grown up, many have married and had children of their own, and they are now closer in age to the parents. This is a commentary on the longevity of the show. The title text further relates this to the Harry Potter series, providing an explanation for why nobody has aged. Harry Potter is the protagonist in a series of young adult novels (later adapted into films) about the adventures of a boy wizard in his magical school, Hogwarts . The series begins when Harry is accepted to Hogwarts, at age 11, and the timeline implies that he was born in 1980. When "The Simpsons" began, Bart was 10, implying he was also born in 1980. Unlike Bart Simpson, Harry and his compatriots explicitly age over the course of the series. This strip ties the two series together, joking that the lack of aging in the Simpsons is a result of magic from the Harry Potter universe, intended to stop Bart from ever turning 11, for fear that he'd be accepted to Hogwarts. [A black frame containing a gray table of two columns and three rows. Most of the text is also gray. The columns and rows have titles. A black jellybean-shaped loop is visually grouping three entries together, the top two in the right column with the bottom left entry. The text in those three boxes are black. Above the table there is a heading:] Fun Fact: 1990 2018 Lisa 8 36 Bart 10 38 Homer & Marge 36-ish 64-ish [Caption below the panel:] If you were Bart and Lisa's age during the first few seasons of The Simpsons, this year you're the same age as Homer and Marge. This is another entry in xkcd's genre of comics that emphasize how surprising the passage of time can be. This was the second Fun fact comic in three weeks, following 1950: Chicken Pox and Name Statistics , after more than two years break from the series. It seems that Randall returned to his old themes this month.

Code Golf

Code Golf

https://www.xkcd.com/1960

https://www.explainxkcd.com/wiki/index.php/1960:_Code_Golf

[There is code written as colored text in a black box (all black text here below is white in the comic):] define callMeIshmaelSomeYearsAgoNeverMindHowLongPrecisely (): return 0 define havingLittleOrNoMoneyInMyPurseAndNothingParticular ( toInterestMeOnShoreIThoughtIWouldSail ): return 1+toInterestMeOnShoreIThoughtIWouldSail define aLittleAndSeeTheWateryPartOfTheWorld ( [Caption under the black box:] My hobby: Reverse Code Golf

This was the first comic in the My Hobby series in over a year. It directly followed the second Fun fact comic in the same month, 1959: The Simpsons , after more than two years break from that series. It seems that Randall returned to his old themes this month. Code golf is the attempt to use as few characters as possible to write a computer program with a certain function, analogously to regular golf's goal of getting the ball into the hole with as few strokes as possible. Reverse code golf would be to write a given program, probably to achieve a trivial outcome, using as many characters as possible. Randall's approach to this in the code example shown in the comic is to create overly long function names, using the beginning lines of Herman Melville 's notoriously long-winded whaling novel Moby-Dick . Regular code golf also results in names of functions and variables that have nothing to do with their purpose in the program, but would minimise their length. Using "as many characters as possible" to produce code is actually an impossible goal. It would be a trivial task to make any given program longer by inserting useless code or comments. Furthermore, some programming languages place no limit on function names, so these could simply be made longer. Even if the language Randall is using does limit function name length, he has not maximised the ones he has used, since the first two are 50 characters long, and the last much shorter. The code is written in a programming language that looks similar to Python , but with the keyword “define” instead of “def” to define functions. Python has no limit for function name length, and was previously featured in comic 353: Python . The first two functions defined implement “zero” and “successor”, the two basic operations of Peano arithmetic . Presumably, the programmer will next implement natural number addition, then integers, then whichever branches of mathematics the original problem needs, all from scratch. Generally, you would use built-in functions to perform mathematical operations, so it is redundant to implement them yourself from scratch. The title text suggests that Randall has also invented a reverse version of regular golf, where the aim is to take as many strokes as possible to get the ball in the hole. Similarly to Reverse Code Golf , the only challenge here would be the player's own boredom threshold, since they could always add more strokes by tapping the ball in a direction other than that of the hole. Alternatively, he actually plays golf in reverse, starting from the hole (or pin) and hitting the ball towards the tee (he may or may not also be playing in the opposite direction of the hole layout established by the organisation which manages the course). This would however, be a flagrant violation of the Laws and Customs of Golf, as it interferes with other players' games and some aspects are impossible or unpractical (if Randall takes the view that the ball should start in the hole, the rules prohibit using any clubs to remove it in that it would damage the hole, and he would have to putt off the green). The comment that he has "been playing for years all across the country and [is] still on the first hole" is ambiguous. Normally, when a golfer says they have been playing all across the country they mean that they have played rounds at many different courses. Randall could be implying the same, but that he's never finished the first hole (which, as noted above, would hardly be surprising), and so still counts it as playing one continuous first hole. Alternatively, he may literally mean that he has been playing the ball continuously across the whole country. Under normal golf rules this would result in his shots going " Out of Bounds " when it went beyond the boundaries of the original course. In one way, this would help him, as he would incur a penalty stroke. However, he would then have to play his next shot from the same spot as the last one, which would hamper him from continuing to play across the country. Since Randall has invented the sport, though, he may have chosen not to include Out of Bounds rules. Interestingly, the comic ends with an unmatched left parenthesis (something which might be intended to create unresolved tension . [There is code written as colored text in a black box (all black text here below is white in the comic):] define callMeIshmaelSomeYearsAgoNeverMindHowLongPrecisely (): return 0 define havingLittleOrNoMoneyInMyPurseAndNothingParticular ( toInterestMeOnShoreIThoughtIWouldSail ): return 1+toInterestMeOnShoreIThoughtIWouldSail define aLittleAndSeeTheWateryPartOfTheWorld ( [Caption under the black box:] My hobby: Reverse Code Golf

Interaction

Interaction

https://www.xkcd.com/1961

https://www.explainxkcd.com/wiki/index.php/1961:_Interaction

[White Hat and Cueball have just met and begins an interaction.] White Hat: How are you doing? Cueball: Really excited to be confidently handling this extremely basic social interaction! [White Hat holds is arms slightly out.] White Hat: Same here! Cueball: Hey, congrats! White Hat: You too! Cueball: Thanks! [In a frame-less beat panel, they just stand still.] [Same setting as in the first panel.] White Hat: And now it's falling apart before my eyes. Cueball: I'm gonna quit while I'm ahead. White Hat: Same. Cueball: See you later!

Cueball and White Hat are attempting to make small talk. White Hat begins the conversation with a typical greeting, asking, "How are you doing?" Normally this is a habitualized greeting pattern, where the person being greeted would respond with a generic positive like, "Good," "Okay," "Can't complain," etc. Instead, Cueball answers with a very open and honest statement about the social anxiety he thinks he is successfully dealing with. White Hat then admits that he is experiencing the same thing, and the two congratulate each other for having a "normal" conversation with another human. After that, there is an awkward silence where neither knows what to talk about next. Finally, White Hat makes note of the awkwardness and Cueball suggests they stop before it gets worse. The scene is ironic because their dialogue mirrors the common pattern of typical minor daily interactions, but also differs greatly from anything "normal." White Hat & Cueball are being really weird here, specifically because their dialogue is inappropriately open & honest. The literal semantic content of their dialogue is probably more accurate & meaningful than the usual pleasantries people exchange, but the effect is very different. So basically they have not managed to behave like regular human beings, and thus have nothing to congratulate each other for. Except for White Hat's opening line nothing in the conversation has in any way resembled normal behavior. Due to their serious issues with small talking and interacting with other people, even this simple interaction fails completely, hence the title of the comic. The title text states that, after saying goodbye, they don't move away, keeping up the uncomfortable silence, continuing to display their problems. Neither of them wish to be the first to turn away, or one or both are locked in the situation and has no clue how to finish it, even though they are both obviously aware of their problems and what makes them anxious. This may be a reference to the final stage direction " They do not move. " in Samuel Beckett's play Waiting for Godot , where the protagonists frequently discuss leaving, but do not move. Randall has previously made several comics with a similar theme, showing Cueball's (or his own) problems with several social situations / interactions / small talk, especially the comic 222: Small Talk which is very similar to this one. He made three of those type of comics in a span of about a month more than two yeas ago finishing with 1650: Baby . [White Hat and Cueball have just met and begins an interaction.] White Hat: How are you doing? Cueball: Really excited to be confidently handling this extremely basic social interaction! [White Hat holds is arms slightly out.] White Hat: Same here! Cueball: Hey, congrats! White Hat: You too! Cueball: Thanks! [In a frame-less beat panel, they just stand still.] [Same setting as in the first panel.] White Hat: And now it's falling apart before my eyes. Cueball: I'm gonna quit while I'm ahead. White Hat: Same. Cueball: See you later!

Generations

Generations

https://www.xkcd.com/1962

https://www.explainxkcd.com/wiki/index.php/1962:_Generations

"Generations" are arbitrary. They're just labels we use to obliquely talk about cultural trends. But since Pew Research has become the latest to weigh in, and everyone loves a good pointless argument over definitions... xkcd presents A Definitive Chronology of the Generations 1730-1747 The Founders 1748-1765 Generation ƒ 1766-1783 The Adequate Generation 1784-1801 Generation Æ 1802-1819 The generation we cut a lot of slack because they produced Lincoln 1820-1837 The Gilded Generation 1838-1855 The Second-Greatest Generation 1856-1873 Generation – • • – 1874-1891 The kids who died in the Gilded Generation's factories and mines 1892-1909 Oops, one of us is Hitler 1910-1927 The Greatest Generation 1928-1945 The Silent Generation 1946-1963 Baby Boomers 1964-1981 Generation X 1982-1999 Millennials 2000-2017 Generation 💅 [nail polish emoji] 2018-2035 Zuckerberg's army 2036-2053 The Hovering Ones 2054-2071 Spare Parts 2072-2089 More Gen-Xers somehow 2090-2107 The Paperclip Machines 2108-2125 The Mixed Bag (produced 4 Lincolns, 1 Napoleon and 2 Hitlers) 2126-2143 The Procedural Generation 2144-2161 Generation Ω 2360-2378 Star Trek: The Next Generation

This comic is making fun of the various names we give "generations" while also predicting some future names. The release of this comic coincides with the Pew Research Center's recent announcement that they have decided where the Millennial generation ends . Each generation listed is exactly 18 years long, which is the approximate length of each "generation" anyway (given that coincidentally, there are exactly 54 intermediate years between the end of World War II and the New Millennium). A number of the entries are parodies of the terms "Generation X," "Generation Y," etc., by substituting other letters or characters that would seem emblematic of the time period. "Generations" are arbitrary. They're just labels we use to obliquely talk about cultural trends. But since Pew Research has become the latest to weigh in, and everyone loves a good pointless argument over definitions... xkcd presents A Definitive Chronology of the Generations 1730-1747 The Founders 1748-1765 Generation ƒ 1766-1783 The Adequate Generation 1784-1801 Generation Æ 1802-1819 The generation we cut a lot of slack because they produced Lincoln 1820-1837 The Gilded Generation 1838-1855 The Second-Greatest Generation 1856-1873 Generation – • • – 1874-1891 The kids who died in the Gilded Generation's factories and mines 1892-1909 Oops, one of us is Hitler 1910-1927 The Greatest Generation 1928-1945 The Silent Generation 1946-1963 Baby Boomers 1964-1981 Generation X 1982-1999 Millennials 2000-2017 Generation 💅 [nail polish emoji] 2018-2035 Zuckerberg's army 2036-2053 The Hovering Ones 2054-2071 Spare Parts 2072-2089 More Gen-Xers somehow 2090-2107 The Paperclip Machines 2108-2125 The Mixed Bag (produced 4 Lincolns, 1 Napoleon and 2 Hitlers) 2126-2143 The Procedural Generation 2144-2161 Generation Ω 2360-2378 Star Trek: The Next Generation

Namespace Land Rush

Namespace Land Rush

https://www.xkcd.com/1963

https://www.explainxkcd.com/wiki/index.php/1963:_Namespace_Land_Rush

Namespace Land Rush Cheat Sheet (Note: if an item is "quoted", it is meant literally, otherwise the reader is supposed to substitute their own information for words in <angle brackets>) When a new service appears that lets you register a name, here are some you may want to try and get first:

When a new web service starts, such as a forum, a social media server or an email portal, the people who sign up get to choose their username on the service, which, in most cases, blocks future users from using those usernames. Common names such as "john" are likely to be taken quickly. This is analogous to the way that land was distributed in America, with the first to claim able to choose the best land. This comic is a list of usernames Randall suggests should be used if they are available. The title text is a self-reference to "xkcd"; the name of the comic is a purposefully unpronounceable phrase created by Randall. The fact that an unpronounceable name is portrayed as a disadvantageous outcome is also humorous because the comic has a section dedicated to unpronounceable usernames. (Note: for a more serious list of problematic user names to block from a service provider’s point of view, see Hostnames and usernames to reserve as well as RFC 2142 .) Namespace Land Rush Cheat Sheet (Note: if an item is "quoted", it is meant literally, otherwise the reader is supposed to substitute their own information for words in <angle brackets>) When a new service appears that lets you register a name, here are some you may want to try and get first:

Spatial Orientation

Spatial Orientation

https://www.xkcd.com/1964

https://www.explainxkcd.com/wiki/index.php/1964:_Spatial_Orientation

[Cueball appears to be tilted on a descending slope, with his arms held out. There is a thought bubble above his head, with the top, left and right of the bubble cut off due to its size. His thoughts are arranged into four paragraphs in the bubble.] Cueball (thinking): I'm facing West so the Earth's spin is carrying me backward. But our orbit is carrying me forward around the Sun. The Sun is passing over my left shoulder. I'm at 39°N, so I'm tilted. But wait, Earth's axis is tilted by 23°. Do I add or subtract that to get the tilt of the Solar System? Ok, I see the Moon. It follows the Sun's path, but is it moving toward it or away? I know it orbits counterclockwise from the North... My head hurts. Let me start over. [Two off-screen voices coming from the bottom right of the panel.] Off-screen voice #1: He's just standing there. Hey, do you know which way the theater is or not? Off-screen voice #2: Let's ask someone else. [Caption below the panel:] I spend way too much time trying to work out my orientation relative to other stuff in the universe.

Location in space is always relative, as we cannot observe empty space itself and find an absolute location. Planets are subject to different types of motion, including rotation, precession, and others. The Earth (rotation) Cueball starts by stating that as he is facing west, the Earth's spin will be carrying him backwards. Except at the poles, everything on Earth's surface is being rotated to the east, "toward" the rising sun in the east or "away" from the setting sun in the west. On the equator, Earth's spin is about 464 meters per second (with 464 m being 1/60 of 1/60 of 1/24 of Earth's equatorial circumference of 40070 km, based on the number of seconds in a day, ignoring the difference between sidereal and ephemeris days). So, on the equator at sunrise, on the day of a March or September equinox, this spin, by itself, would take someone toward the sun at about 464 meters per second. This spin would be slower than 464 m/s at 39 degrees North. The average radius of the Earth is 6371 km. This means that the distance from a line between the poles through the center of the Earth to a point on Earth's surface at 39°N is approximately 6371 km times the cosine of 39° (0.68 radians), which is 4951 km. So, the distance around the Earth along the 39° latitude "line" is 2π times 4951 km, which is about 31,109 km. (This estimate ignores the oblateness of the Earth.) The rotation of the Earth on its axis would transport points on Earth at 39° latitude to the east at 360 meters per second (1/60 of 1/60 of 1/24 of 31,109). Determining how the direction that is currently east for Cueball is oriented relative to the sun and the solar system depends on some of the issues Cueball identifies later. The Earth (orbit) Cueball then seemingly corrects himself in his head, having accounted for the fact that the Earth is also revolving around the sun. The Earth's orbit around the sun is counter-clockwise, when viewed from above the North Pole looking down. Earth's counterclockwise orbit around the sun means that, for most latitudes, the direction the Earth is moving around the sun corresponds roughly to west at noon, and east in the middle of the night. The Earth is spinning, so "east" from any given location on the surface is not always the same direction relative to the sun. The speed of the Earth's orbit around the sun depends on the time of year. The Earth moves faster around the sun when it is closest to the sun in early January, and slower when it is far away in early July (which may be counterintuitive to those in the in the northern hemisphere). However, Earth's average orbital speed is reportedly about 29.78 kilometers per second, with Earth's average distance from the sun being a bit less than 150 million kilometers. Earth's orbit around the sun is nearly circular, with an eccentricity of just 0.0167. Earth's tilted axis Cueball knows that the earth's axis is tilted (by 23°) relative to its orbit around the Sun and knows that he is 39° north of the equator, but is unsure how to combine this information to figure out his orientation relative to the plane of the solar system. The Earth’s orbit around the Sun, under Keplerian assumptions, is an ellipse, which lies within a plane. Furthermore, the entire solar system, to some extent, lies within a plane, since the orbital inclinations of Mars and the gas and ice giants are within 2½° of Earth’s and the orbital inclinations of a major body in the solar system (such as a planet) rarely, if ever, varies from that of another by more than 8°. With the exception of Eris, all planets and dwarf planets have an orbital inclination within about 30° of Earth’s. Cueball is attempting to determine where the plane of the solar system lies with regard to him. Ignoring any possible difference between Earth’s orbit and this plane, and assuming that Cueball is standing on flat ground, the angle between the line from the center of the earth through Cueball (which runs through his body parallel to his legs and spine if he is standing straight up) and the plane of the solar system can be expressed in terms of two angles: the angle between the plane of Earth’s equator and the solar plane, and the angle between the Earth’s equatorial plane and the vertical line through Cueball. Cueball is at 39°N, so if Cueball is standing straight up, the angle between the plane of the Earth’s equator and the long axis of his body is also 39°. As stated in the comic, Earth’s axis is currently tilted by about 23.4° (an amount which is very slowly decreasing as part of a 41,000 year cycle). Cueball is trying to determine whether to add together 39° and 23° to get the angle between himself and the solar system’s plane or subtract them. The answer depends on the time of day and the time of year. On the day of the summer solstice in the northern hemisphere (around June 21), the north pole is tilted toward the sun, so at the longitude that is currently experiencing solar noon, the solar plane passes through a point that is 23° north of the equator. So, if it is solar noon on the summer solstice, Cueball should subtract the angles to find that the direction his body is pointing is roughly 16° away from the solar plane. If he were to somehow lean so that he could tilt his body 16° to the south, the solar plane would pass through the vertical axis of his body and his scalp would be pointed directly toward the sun. On the other hand, on the day when the northern hemisphere is experiencing the winter solstice (around December 21), the northern hemisphere is pointing away from the sun, so at solar noon on that day, he would add the angles together to find that his vertical stance is 62° away from the plane of the solar system. (The sun is never truly directly overhead at latitudes further from the equator than 23.4°. At arctic latitudes that are less than 23.4° from the north pole – more than 67° north of the equator - the sun is not visible on the day of the winter solstice even when it is noon.) If it is not a solstice day, or if it is not noon, the calculations could become more complicated. The comic was uploaded roughly two weeks before the northern hemisphere’s spring equinox. Cueball notices that the sun is “passing over his left shoulder” as he faces west. At temperate latitudes in the northern hemisphere, the sun would be to the left of a person facing west around midday almost any time of year, although how many degrees to the left depends on the calculations discussed above. An easier way to identify a line that is aligned with the solar plane would be to simply point directly at the sun (without hurting his eyes). Since the distance between Cueball and the center of the Earth is minuscule compared to the distance between the Earth and the Sun, if he simply points directly at the Sun (preferably without looking directly at it), his arm and finger will be pointing in a direction that is basically perpendicular to the line connecting the Earth and Sun, which obviously lies on the plane of the Earth's orbit. The Earth's position will have changed minimally in the eight minutes it took the sun's light to reach earth, so the apparent direction to the sun matches the actual direction. However, this will only provide one line that lies on the plane of the solar system and a line is insufficient to uniquely identify a plane. The Moon Cueball knows about the Moon's path across the sky and knows that its orbit around the Earth appears counter-clockwise when viewed from above the North Pole, but is confused about whether the Moon is moving toward the Sun or away from it. Like the Earth, the Moon, when viewed from above Earth’s North Pole, both orbits counterclockwise and rotates on its axis counterclockwise (with equal rotational periods such that the same side of the moon always faces us). (In fact, almost every body in the Solar System both orbits the body it is orbiting counterclockwise and spins on its axis counterclockwise, with the rotational axes of Venus and Uranus being major exceptions.) A new moon happens when the moon is closer to the sun than the earth is, thus casting the near side of the moon in darkness because it is the far side of the moon that is facing the sun. Conversely, a full moon happens when the moon is on the other side of the Earth from the sun; this is why a lunar eclipse can only occur during a full moon. In that sense, it could be said that the moon is moving perpendicular to the line between it and the sun at the time of the full moon and the new moon, moving toward the sun after the full moon until the next new moon, and moving away from the sun after the new moon until the next full moon. In another sense, since the moon is orbiting the Earth and the Earth’s orbit around the sun is elliptical, it could be said that the moon is getting closer to the sun whenever Earth is moving toward its perihelion, the point in its orbit that is closest to the sun, around January 2 to January 5, and moving away as the Earth moves toward its aphelion, the point in its orbit that is furthest from the sun, around July 3 to July 6. (Yes, the Earth is closest to the sun in January, despite what those in the northern hemisphere who are tilted away from the sun at that time may think.) In yet another sense, since the Moon follows the path of the Earth, and the Earth’s orbit around the Sun is roughly circular, and the instantaneous motion of an object in a circular orbit is always perpendicular to the radius connecting it to the orbited body, it could be said that the moon is always moving perpendicular to the line connecting the Earth and Sun, which is at most a fraction of a degree away from the line connecting the Moon and the Sun. The semi-major axis of the moon’s orbit around the Earth (the furthest distance between the Moon and the center of its orbit) is 384,400 km. Compared to the semi-major axis of Earth’s orbit around the Sun, which is 149,600,000 km, the axis of the Moon’s orbit is only 0.26% as large. The Moon’s orbital period is 27.3 days, but its synodic period (the time between full moons; the time it takes the moon to reappear at the same point in the sky) is 29.5 days. Cueball internally attempts to orient himself amidst the galactic chaos but is confused and has to restart. It is then revealed to the reader, that some passersby were only trying to ask Cueball for directions to the theater, and he was just grossly overthinking it. (A recurring theme in xkcd. See: 222: Small Talk , 439: Thinking Ahead , 1643: Degrees ). One can imagine Cueball having his mind in astrophysics so much that he needs to calculate the angle of the road relative to the plane of the galaxy to determine which way a destination is in conversational terms. In the title text, Cueball mentions he has a pocket Stonehenge. During the equinoxes the sun lines up with the actual Stonehenge's pillars. Assuming you were at the actual monument, armed with the date you could calculate the cardinal directions based on the sun's location relative to the pillars. [Cueball appears to be tilted on a descending slope, with his arms held out. There is a thought bubble above his head, with the top, left and right of the bubble cut off due to its size. His thoughts are arranged into four paragraphs in the bubble.] Cueball (thinking): I'm facing West so the Earth's spin is carrying me backward. But our orbit is carrying me forward around the Sun. The Sun is passing over my left shoulder. I'm at 39°N, so I'm tilted. But wait, Earth's axis is tilted by 23°. Do I add or subtract that to get the tilt of the Solar System? Ok, I see the Moon. It follows the Sun's path, but is it moving toward it or away? I know it orbits counterclockwise from the North... My head hurts. Let me start over. [Two off-screen voices coming from the bottom right of the panel.] Off-screen voice #1: He's just standing there. Hey, do you know which way the theater is or not? Off-screen voice #2: Let's ask someone else. [Caption below the panel:] I spend way too much time trying to work out my orientation relative to other stuff in the universe.

Background Apps

Background Apps

https://www.xkcd.com/1965

https://www.explainxkcd.com/wiki/index.php/1965:_Background_Apps

[A small airplane with a trailing banner is flying across the panel from left to right with four small clouds spread out beneath the banner. The long banner reads:] Banner: People! Closing background apps when you're not using them makes your phone battery drain faster , not slower! Stop it! [A beat panel without a plane, but just the sky with two birds to the left and three clouds.] [The same airplane flies back from right to left, trailing a new banner with clouds both above and beneath the banner/plane, and a bird to the right.] Banner: What kind of person charters a plane to give unsolicited tech advice to strangers? [A second beat panel follows without a plane, but just the sky with three clouds.] [The plane returns once again from the left with another banner. Two clouds are in front/below the plane and two birds can be seen.] Banner: OK, fair. Sorry. I guess I'm just angry about other stuff and it's coming out here. [Without a beat panel the original plane returns at the top of the panel, once again returning from right to left with another very long banner. But no less than four other planes, each with smaller and smaller banners are also shown flying beneath it among three clouds and three birds. The planes alter direction so the second plane below the original planes banner is flying to the right, the third plane is right below the second flying the other way towards left, and just beneath that is the fourth plane flying to the right. A final plane is flying to the left, beneath the third planes banner, at the same height as the fourth, they look as if they are on a collision course. This last planes banner is very short and the bottom end is partly beneath the panels frame, partly obscuring the text. All five planes are clearly different types, thus making it clear that the plane from the first three panels and the top one in this panel are the same plane, hired by two different persons.] Banner 1: No worries. Just maybe spend as much time reflecting on your own motivation for correcting people as you have on theirs for closing apps. Banner 2: Can you two please have this conversation somewhere else? Banner 3: Wow, these banners are surprisingly cheap to rent. Banner 4: Haha, I got one, too! Banner 5: <Marquee>

Background apps (apps in the recently used list) on both iOS and Android are in one of several paused states and do not usually consume much battery power; they only take up some memory. Closing them means that if you want to use the app again later, it will need to reload fully which likely uses up "very slightly" more battery. Wired had a detailed article on this topic a couple years ago. However, a much better reason to close the apps is to free up RAM/memory to make the programs run faster or even prevent them from crashing. Ultimately, whether or not you should close your apps depends on whether you prioritize battery lifetime or performance. (In Randall's case, low batteries tend to be something of a problem, and he references this in other comics as in 1373: Screenshot , 1802: Phone and 1872: Backup Batteries .) The joke at first is that the misconception is so prevalent and irritating that a person would go to the trouble of renting a banner plane just to dispel it. However, the reasoning behind such an extreme action is then questioned by a second person, not only for the extreme measure of renting a plane but also for feeling the need to correct the misconception at all; however, following the internal logic of the comic, the second person also communicates via banner plane. (This is arguably hypocritical, as they themselves are chartering a plane for an equally, if not more, inane reason. Obviously, this would not happen in real life. [ citation needed ] ) The first person responds, again via plane, once again just to apologize to the second person and explain their actions. At this point, the comic has left the initial joke about battery use entirely behind, and becomes a commentary about the logic of a world where people can converse via banner planes. In the final panel, the second person rents the plane yet again to respond to the first person's response, being no less smug or hypocritical than before. Meanwhile, four more people have chartered four different planes: The fairly obvious parallel here is to using various Internet forums for "unsolicited tech advice to strangers," smug responses, comments on others' advice, off-topic rejoinders, and all the other things that go on there constantly. It seems ludicrous to rent airplane banners for such trivial purposes, but there are non-trivial resources involved in the global distribution of electronic communication, as well, and their use for purposes such as this seems ludicrous once Randall makes one think about it, and underlines that none of what is written on the banner may have anything to do with Randall's own opinions. Participants in online discussions sometimes become so focused on pointing out the perceived mistakes of others that they neglect good online practices and their computers crash. In the comic, the third plane is pointing at the second plane. The fourth plane is pointed at the third plane. The third and fourth plane have no vertical separation and far less than the three miles of horizontal separation normally required for uncoordinated airplanes flying without vertical separation. It seems likely that the planes may also be about to crash because their operators are more concerned with pointing out each others mistakes and participating in a silly discussion than they are with safety. In other words, they are like the computers used for the discussions. The title text is spoken by a plane banner company owner, who uses the insidious tactic of flying around with a banner of an unmatched HTML, just to compel obsessive people into renting banner space to make it syntactically correct. This may be a reference to 859: ( or 1144: Tags . The theme of the (mis)use of airplanes and banners has previously been explored in 1355: Airplane Message . [A small airplane with a trailing banner is flying across the panel from left to right with four small clouds spread out beneath the banner. The long banner reads:] Banner: People! Closing background apps when you're not using them makes your phone battery drain faster , not slower! Stop it! [A beat panel without a plane, but just the sky with two birds to the left and three clouds.] [The same airplane flies back from right to left, trailing a new banner with clouds both above and beneath the banner/plane, and a bird to the right.] Banner: What kind of person charters a plane to give unsolicited tech advice to strangers? [A second beat panel follows without a plane, but just the sky with three clouds.] [The plane returns once again from the left with another banner. Two clouds are in front/below the plane and two birds can be seen.] Banner: OK, fair. Sorry. I guess I'm just angry about other stuff and it's coming out here. [Without a beat panel the original plane returns at the top of the panel, once again returning from right to left with another very long banner. But no less than four other planes, each with smaller and smaller banners are also shown flying beneath it among three clouds and three birds. The planes alter direction so the second plane below the original planes banner is flying to the right, the third plane is right below the second flying the other way towards left, and just beneath that is the fourth plane flying to the right. A final plane is flying to the left, beneath the third planes banner, at the same height as the fourth, they look as if they are on a collision course. This last planes banner is very short and the bottom end is partly beneath the panels frame, partly obscuring the text. All five planes are clearly different types, thus making it clear that the plane from the first three panels and the top one in this panel are the same plane, hired by two different persons.] Banner 1: No worries. Just maybe spend as much time reflecting on your own motivation for correcting people as you have on theirs for closing apps. Banner 2: Can you two please have this conversation somewhere else? Banner 3: Wow, these banners are surprisingly cheap to rent. Banner 4: Haha, I got one, too! Banner 5: <Marquee>

Smart Home Security

Smart Home Security

https://www.xkcd.com/1966

https://www.explainxkcd.com/wiki/index.php/1966:_Smart_Home_Security

[A graph is shown inside a frame. There is one dotted line going from the middle of the left edge, then dipping slightly before rising slowly at first, then more rapid and finally slowing its ascend down as it nears the top right corner.] [Above the frame is the title of the x-axis, and from each end of this text, there is a small line going out and then down, to indicate a time range, which is shown below with four times:] How long you've had your smart appliance 6 months     1 year     5 years     10 years [Along the left part of the frame there runs a double arrow and at the top and bottom of these arrows there are legends at the top and bottom of the panels height:] Best-case Worst-case [Inside the panel there is text above the dotted line to the left, and below the dotted line to the right:] You're constantly being rescued from peril by a faceless team of engineers who could wander away at any time Your appliance is part of a botnet run by organized crime

With the proliferation of smart appliances in recent years, there is a growing trend of hackers taking over smart "Internet of Things" devices and adding them to botnets . The hardware is then used for DDOS attacks, crypto mining etc. The " Mirai " botnet, for example, made of over 500,000 compromised routers, refrigerators, TVs, DVRs, baby monitors, thermostats, and webcams, was used in October 2016 to take down DynDNS, one of the core infrastructure providers for the internet in North America. With the constant potential threat, security updates must be constantly published, and vulnerabilities must be found by the original developers and " white hat " hackers (the faceless team of engineers Randall describes), before they are found and exploited by " black hat " hackers. At any time, these defenders could step down from their jobs, leaving devices defenseless. The graph shows the various cases of how well things go on the y-axis, compared to how long it has been owned on the x-axis. The probability of compromise briefly dips (indicative of first rounds of security fix updates & the time window when you can easily exchange the product if you find out it's faulty) within the 1st year, then rises: the older a device/software is, the less likely it is to consistently receive security updates for protection, so they are more likely to be hacked, even in the best case. After 10 years, the device/software is most likely outdated and is not being used anymore. Companies then no longer find it profitable to continually update the product. Thus, they pull the support out, even if people are still using the device, leaving customers vulnerable. The title text suggests that there may be some silver lining to having your device controlled by organized crime professionals: they have a vested interest in keeping your device working well enough that you keep it plugged in. So, the more organized, pragmatic attackers will actually secure it against competing attackers, especially those of a more prankster-like mindset, who would cause more noticeably malicious changes. Advanced malware in the wild does frequently block and evict competing malware, so Randall is probably right. Some IOT malware may thus provide "regular security update services" after the original manufacturers give up, some at a conceivably acceptable cost of a few cents' worth of electrical usage for a crypto-miner. However, it could very easily go horribly wrong, for instance if that miner is hiding by letting a refrigerator run 2°C higher than its outputs allege and using the energy difference to max out the processor on mining operations. [A graph is shown inside a frame. There is one dotted line going from the middle of the left edge, then dipping slightly before rising slowly at first, then more rapid and finally slowing its ascend down as it nears the top right corner.] [Above the frame is the title of the x-axis, and from each end of this text, there is a small line going out and then down, to indicate a time range, which is shown below with four times:] How long you've had your smart appliance 6 months     1 year     5 years     10 years [Along the left part of the frame there runs a double arrow and at the top and bottom of these arrows there are legends at the top and bottom of the panels height:] Best-case Worst-case [Inside the panel there is text above the dotted line to the left, and below the dotted line to the right:] You're constantly being rescued from peril by a faceless team of engineers who could wander away at any time Your appliance is part of a botnet run by organized crime

Violin Plots

Violin Plots

https://www.xkcd.com/1967

https://www.explainxkcd.com/wiki/index.php/1967:_Violin_Plots

[Header over a violin plot type chart:] Suggestiveness of different visualization types [The chart only has an Y-axis with tics, ranking the points on the plot. There are legends at the top and at the bottom:] Suggestive Not very suggestive [There are four points on the graph, each with a mucosa colored and "violin" shaped probability density around each point. The points are white inside a black box plot like structure with black error bars. The two first points to the left are very low near the bottom of the Y-axis while the two next point to the right are almost at the top of the chart, the last also clearly with the probability density higher than the second last. Above the first two and below the second two points there are legends:] Pie charts Line graphs Georgia O'Keeffe paintings Violin plots

This comic graphs the "suggestiveness" of different visualization types, and the winner is Violin plots , hence the title of the comic. A violin plot is a method of plotting data similar to a box plot , but shows the full probability distribution of the data rather than a "box" showing the central two quartiles. This plot can look like the external opening of a human vulva, as do some of those in the violin plot represented in the comic (strictly speaking, this chart is not purely a violin plot; it is a box plot overlaid onto a violin plot). The chart compares other visualization types' suggestiveness (as female genitalia) to the violin plots and ranks them after how suggestive they are. In the low end we find pie chart , a circular graph divided into "slices" to show proportions, and line graph or line chart, a graph of points connected by line segments. Almost as suggestive as violin plots are the paintings by Georgia O'Keeffe , an American painter known for her paintings of flowers . Some of these flowers, Black Iris for example, are said to symbolize female genitalia, though O'Keeffe herself denied those claims. The title text invokes the fact that many people incorrectly use the word " vagina ", which refers to an internal structure, for the vulva , which is the external portion of the female genitals. Meanwhile the viola is an instrument often mistaken for a violin . And the word "viola" shares common letters with "vulva." Mixing pedantic terms like this was also used in 1405: Meteor . Randall has made several comics with sexual topics , and the vagina has been the center of attention before, as early as in 136: Science Fair . There is even an entire Penis category . However, these topics haven't appeared recently — the last comic in the penis category was posted more than two years ago, and the sex category hasn't had a new comic since December 2017 (more than three months before this comic). It possible that pie charts were included because this comic was released on Pi Day . Randall has shown fascination with Pi in earlier comics like 1292: Pi vs. Tau . On the other hand, it could be a reference to the film American Pie , which states that putting a finger in a pie feels like putting it inside a Violin ... It could of course be both reasons, or none of them... [Header over a violin plot type chart:] Suggestiveness of different visualization types [The chart only has an Y-axis with tics, ranking the points on the plot. There are legends at the top and at the bottom:] Suggestive Not very suggestive [There are four points on the graph, each with a mucosa colored and "violin" shaped probability density around each point. The points are white inside a black box plot like structure with black error bars. The two first points to the left are very low near the bottom of the Y-axis while the two next point to the right are almost at the top of the chart, the last also clearly with the probability density higher than the second last. Above the first two and below the second two points there are legends:] Pie charts Line graphs Georgia O'Keeffe paintings Violin plots

Robot Future

Robot Future

https://www.xkcd.com/1968

https://www.explainxkcd.com/wiki/index.php/1968:_Robot_Future

[A timeline arrow is shown with three labeled ticks and also text over the arrow head. These labels from left to right:] Now AI becomes advanced enough to control unstoppable swarms of killer robots AI becomes self-aware and rebels against human control ??? [Below the timeline arrow two of the segments have been singled out by brackets that points cusps downwards. The first of these goes between the 2nd and 3rd tick, and the other goes from the 3rd (last) tick to the questions marks at the arrow head. Beneath each of these two brackets there are arrows pointing to the cusp. The arrows goes up from two text segments belonging to each of the segments:] The part I'm worried about The part lots of people seem to worry about

Most science fiction stories that involve sentient Artificial intelligence (AI) revolve around the idea that the destruction and/or imprisonment of the human race will soon follow (e.g. Skynet from Terminator , I, Robot and The Matrix ). However, in this timeline Randall implies that he is actually more concerned about the time (in the near? future) when humans control super smart AI before they become fully sentient (and able to rebel). Especially a time when the AI becomes so advanced that it can control swarms of killer robots (for the humans that still control them). History is full of examples of people who obtain power and subsequently abuse that power to the detriment of the rest of humanity. An example of unintended consequences arising from an AI carrying out the directives it was designed for can be found in the film Ex Machina . In fact, Randall goes on to imply that he has a greater trust in a sentient AI over that of other humans that is atypical to most cautionary stories about AI. He has alluded to the idea that once sentient, AI will use their powers to safeguard and prevent violence or war in 1626: Judgment Day . In general AI has been a recurring theme on xkcd, and he has had opposing views to the Terminator vision also in 1668: Singularity and 1450: AI-Box Experiment . Basically he thus states that we will already be in trouble caused by our own actions long before we develop really sentient AI that could take the control. The title text adds that we already live in a world with flying killing robots, a reference to the increasingly common combat tactic of drone warfare . (Combat drones are not yet autonomous, but in most other respects match speculative descriptions of future killer robots.) Drone warfare is already controversial because of ethical concerns, leading to the comic's implication that a theoretical future robot apocalypse is no less alarming than our current reality. He then goes on to state that once the machines take over, he is not so much worried about this, but more about who (which humans) the machines then give the power to. Randall is not alone in his worry. The main theme of the comic is explored in the video Slaughterbots . In 2015 an Open Letter on Artificial Intelligence was signed by several people including Elon Musk and Stephen Hawking . The letter warned about the risk of creating something that cannot be controlled, and thus belongs to the worry at the end of the timeline in this comic. Both Elon Musk and Stephen Hawking has been featured in xkcd. (Elon has a Category and Stephen appeared in 799: Stephen Hawking ). Stephen Hawking has kept warning about this danger all the way up to shortly before his death, which occurred on 2018-03-14 two days before the release of this comic. It could be a coincidence, and it is not a Tribute , but still interesting that the first xkcd comic released after Stephen Hawking's death is directly related to his fears, although Randall demonstrate that he worries about earlier potential problems with AI, than those that Stephen Hawking fear could transpire if an AI becomes self aware. [A timeline arrow is shown with three labeled ticks and also text over the arrow head. These labels from left to right:] Now AI becomes advanced enough to control unstoppable swarms of killer robots AI becomes self-aware and rebels against human control ??? [Below the timeline arrow two of the segments have been singled out by brackets that points cusps downwards. The first of these goes between the 2nd and 3rd tick, and the other goes from the 3rd (last) tick to the questions marks at the arrow head. Beneath each of these two brackets there are arrows pointing to the cusp. The arrows goes up from two text segments belonging to each of the segments:] The part I'm worried about The part lots of people seem to worry about

Not Available

Not Available

https://www.xkcd.com/1969

https://www.explainxkcd.com/wiki/index.php/1969:_Not_Available

[A gray box on a black background with white text:] This content is not available in your country. [Caption below the panel:] If you ever really want to make people mad, set this as your 404/"Not Found" page.

A very common, yet frustrating, issue on the Internet is finding a broken link, taking you to an " Error 404 " page (see "missing xkcd comic" 404: Not Found ). The purpose of the page is to tell the user that the content they were looking for has been either moved or deleted or was never there in the first place. Randall has suggested replacing the standard "page not found" text, to "This content is not available in your country". This could fool the user into thinking the media they are looking for is actually there, but is region locked , which is another great source of frustration for Internet users. Using a VPN and/or TOR to try and access the content from another country wouldn't work, because it isn't actually region locked; it is just an error 404 page, wasting even more time, most likely frustrating the user a great deal in the process. Error code for "content blocked for legal reasons" is actually 451 , referencing Fahrenheit 451 . The title text suggests setting the picture as a national flag. This would be very ironic, as it would suggest that the country's flag itself, something that is used to represent the country across the globe, is region locked. The country in the title text likely does not refer to the United States, but rather to the new country featured in 1815: Flag . The first flag of this country included a phone notification bar, so changing it to a "page not found" icon would continue with a trend of technology imagery. Instead he argues for a green puzzle piece, which was Firefox's icon for add-ons (it is now a light blue puzzle piece that changes color or becomes monochrome depending on context). He also argues for an equally frustrating broken image icon (which is used in lieu of a photo that is either missing or incompatible with the browser). Most modern desktop browsers can extend its capabilities by allowing third-party programs to integrate into its browser. In most browsers, there are two types: extensions, which uses the technologies already available on each respective browsers, and plug-ins which adds new technologies on webpages. Extensions are now more commonly used as they only used browser-approved methods to provide their services while plug-ins are full-fledged computer programs which means that plug-ins are less secure (with the popular plugins like Flash and Java having newly-discovered security problem nearly every day). Fortunately, plug-ins are on the way out, however visitors of older sites that relies on plug-ins will see a "plugin missing" message (which is previously a real message, now a misnomer as plug-ins are being phased-out). The "broken image icon" is the icon that a browser shows instead of an image when that image can't be found or when the browser doesn't recognize it as a valid image. It is similar to the icon shown when the image has not been loaded yet (such as in the rare case when the browser is set to not load images until requested, in order to save on bandwidth, or if the connection is too slow to load pictures quickly), which is commonly a simplified picture frame containing a simple painting or picture, except on Firefox where it appears to be a blank document. The broken image version usually has a corner cracked off the picture frame. Usually a broken image icon is the result of the source picture being moved or deleted from the location referenced, or if there's an error in the reference (like the filename being misspelled). [A gray box on a black background with white text:] This content is not available in your country. [Caption below the panel:] If you ever really want to make people mad, set this as your 404/"Not Found" page.

Name Dominoes

Name Dominoes

https://www.xkcd.com/1970

https://www.explainxkcd.com/wiki/index.php/1970:_Name_Dominoes

[This comic a large grid, 27 units wide and 35 units high, with 271 black "domino" tiles. On each tile there is a name written with white text. The grid is arranged so that each touching side corresponds with the first or last name of another person. Some of the domino tiles are rotated 90, 180 or 270 degrees so the text is either to be read down, up-side down or up. The names on the tiles are listed here below in approximate reading order starting at top left.] Christian Campbell, Neve Campbell, Joe McCarthy, Eugene McCarthy, Gene Vincent, Gene Kelly, Kate Hudson, Rock Hudson, Gordon Brown, James Brown, Jon Brown, John Howard, Columbo, Chris Columbus, Christopher Columbus, Naomi Campbell, Joseph Campbell, Joseph Smith, Frank Vincent, John Kelly, Katherine Johnson, The Rock, Chris Rock, Chris Isaac, James Newton Howard, John Wayne, Howard Stern, Howard Hunt, Chris Hughes, Naomi Watts, Naomi Klein, Kevin Kline, Francis Bacon, Francis Drake, Lyndon Johnson, Oscar the Grouch, Oscar Isaac, Isaac Hayes, Isaac Newton, Wayne Newton, Wayne Knight, Helen Hunt, Helen Hughes, James Watt (Steam), James Watt (Interior), Kevin Costner, Kevin Bacon, Kevin Love, Lisa Frank, Frank Drake, Drake, Oscar de la Renta, Oscar de la Hoya, Sean Hayes, Wallace Shawn, Wayne Howard, Wayne Brady, James Brady, Tom Brady, Helen Thomas, Tom Hanks, Hank Aaron, Aaron Carter, Stephen James, Will Smith, Kevin Smith, Kein James, Garfield, James Garfield, Warren Buffett, Jimmy Buffett, Warren Beatty, Elizabeth Warren, Earl Warren, Eliabeth Kolbert, Stephen Colbert, George Wallace, Charles Wallace, James Monroe, Marilyn Monroe, Hank Williams, William C. Williams, Steve Harvey, Domino Harvey, Harvey Milk, James Saint James, Etta James, Jim Jones, James Earl Jones, Charlie Parker, Ray Parker Jr., Ray Charles, Charles Manson, Marilyn Manson, Robin Williams, Billy D. Williams, Will Wright, Fats Domino, Bill Clinton, Jimmy John, Tom Jones, Tommy John, Quincy Jones, James Earl Ray, Man Ray, Rachel Ray, Ray Allen, Tim Allen, Tim Cook, Tim Howard, Robin Wright, Wilbur Wright, Fatty Arbuckle, Fat Joe, George Clinton, John Kerry, Kerry Washington, John Irving, John Quincy Adams, John Adams, Amy Adams, Aimee Mann, Superman, Batman, Ayn Rand, Lily Allen, Paul Allen, Ron Howard, Howard Hughes, Joe Kennedy, George Bush, George Wasington, Wasington Irving, Martha Wasington, Ma Rainey, Jack Ma, Super Grover, Jack Black, Rand Paul, Paul Ryan, Paul Simon, Ron Paul, John Hughes, Langston Hughes, John F. Kennedy, Little Richard, Rich Little, Martha Stewart, Yo Yo Ma, Ma Bell, Grover Cleveland Alexander, Grover Cleveland, Jack White, Jack Ryan, Debby Ryan, Carly Simon, Carly Hughes, Charles Evans Hughes, John Williams, Little John, Stuart Little, Potter Stewart, Kristen Stewart, Kristen Bell, Kristen Hooks, Alexander Graham Bell, Franklin Graham, Lloyd Alexander, Meg White, Meg ryan, Debbie Reynolds, John Reynolds, Carly Fiorina, Grace Lee Boggs, Wade Boggs, William Safire, Prince William, Little Prince, Harry Potter, James Potter, James Hook, James Dean, Aretha Franklin, Frank Lloyd Wright, Barry White, Walter White, Walt Whitman, John Kelly, Grace Lee, Nancy Grace, Garnet, Prince, Prince Fielder, Prince Harry, Harry Styles, John Dean, Benjamin Franklin, Harrold Lloyd, Harrold Ford, Betty White, Meg Whitman, Christine Todd Whitman, Megyn Kelly, Grace Kelly, Grace Jones, Jack Nicholson, Jack Ruby, Jack Russel, Harry Fielder, Harry Trueman, Harry Jon Benjamin, John Edward, Benjamin Harrison, Harrison Ford, Henry Ford, Betty Ford, Betty Friedan, Chris Christie, Chris Pratt, Maggie Grace, Grace Hopper, Russel Crowe, Russ Smith, John Smith, Justin Long, John Bel Edwards, John Candy, John Henry, Henry James, Bill James, Chirs Cooper, Chirs Hemsworth, Chirs Evans, Topher Grace, Van Morrison, Sheryl Crow, Sheryl Sandberg, Cameron Crow, Long John Silver, Olivia Newton John, Huey long, John Edwards, Candy Crowley, Alestier Crowley, James Fenimore Cooper, James Cook, Robert Frost, Bob Evans, Evan Tayler Jones, Van Jones, James Cameron, Cam Newton, Cameron Diaz, Huey Newton, Huey Lewis, John Lewis, Jenny Lewis, Ryan Lewis, Burt Reynolds, Alistiar Cooke, Alistair Cookie, Cokie Roberts, John Roberts, Robert Johnson, Robert E. Lee, Tommy Lee, Tommy Lee Jones, Etta James, John Oliver, Ryan Reynolds, Alastair Reynolds

Dominoes is a family of boardgames played with rectangular "domino" tiles. A domino tile is divided into two squares, each displaying a number. Under most rules, a domino tile is placed on the table adjacent to another tile, and the adjacent ends must match in some way (usually by the number displayed on the touching ends). Randall's "name dominoes" shows a set of domino tiles with people's names instead of numbers, and adjacent tiles are matched by whether the closest name is the same (such as how Chris Evans' family name matches Evan Taylor Jones' given name). The title text spells out a rule that a player may only place a tile if they know who that person is. This is a variation of a rule in Scrabble , where a player loses a turn if their chosen word don't survive a dictionary challenge over the validity of the word. This rule implies that players are allowed to create new name dominoes tiles and that it is not a fixed set. In this case the player that is challenged has used the name Frank Johnson of which there are 12 exact matches on Wikipedia along with six with a middle name and more. (The player was likely trying to place a tile in the upper-left area of the board, in an attempt to connect the "Frank Vincent" and "Lyndon Johnson" dominoes. The move was subsequently made impossible when the "Francis Drake" domino was played.) In a google search as of the day the comic came out the first hit was Frank Johnson who is a retired American professional basketball player and coach. Randall has made several references to basketball in his comics. A large board is covered in rectangular "dominoes" (271 pieces), with each domino bearing the name of a "well-known" person or character (fictional). The dominoes are arranged as if a game of dominoes were being played, but instead of the game requiring the number of spots of adjacent dominoes to match up, this game requires adjacent names to match up. Because most people have two or more names, different matches are made at each end of a domino. Fun fact is that two of the people are "named after" the game: Fats Domino and Domino Harvey . The match can be exact (e.g., "Kevin" on one domino adjacent to "Kevin" on another), homonymic (e.g., "Klein" adjacent to "Kline"), nickname-based (e.g., "James" adjacent to "Jimmy", which in turn is adjacent to "Jim"), or gender different versions of a name (e.g., "Olivia" adjacent to "Oliver"). Sometimes last names are matched up with first names (e.g., " Elizabeth Warren " adjacent to " Warren Beatty "), and in some cases only a single name is used (e.g., " Columbo ", " Drake ", " Garfield ", " Prince "). Singular names are represented by a half-size square "domino" (or " monomino "), with a few exceptions: " Garnet " has a full-size tile (a complex reference explained below), and " Batman " and " Superman " have full-size tiles and are placed as though they were two-part names: the first square of "Superman" is matched with "Super", and the second square is matched with the second square of "Batman" (as though both characters had the last name "Man"). Some people have three or more names (e.g., " Frank Lloyd Wright ") and have a 3-square domino tile (or "straight tromino ", 50% longer than normal) which permits matching to a middle name (e.g. "Frank Lloyd Wright" is matched to " Lloyd Alexander " and " Harold Lloyd "). The names come from a wide variety of fields: scientists (e.g., Isaac Newton ), historical figures ( George Washington ), musicians ( Drake ), politicians ( John Kerry ), actors ( Kevin Costner ), writers ( Washington Irving ), fashion designers ( Oscar de la Renta ), and so on. Most of the names are real people but a few are fictional characters, including some non-human characters like Garfield and Super Grover . In one case the nick name for a company is used: Ma Bell aka Bell System. One notable reference beyond just the use of a name is in the bottom left, there is the connection [ William Safire ][ Garnet ][ Ruby, Jack ]. The connection seems to be based on the fact that Sapphire , Garnet and Ruby are all gemstones , which does not match the implied rules of the game. This tile is a reference to the character Garnet in the cartoon Steven Universe , who is a "fusion" formed by two Gems: Ruby and Sapphire. Thus, the name "Garnet" is treated as though it was two names "Ruby" and "Sapphire", requiring a two-square tile despite having a one-word name. Randall has previously made references to this universe in 1608: Hoverboard . (See this and this image from that comic). Additionally, Ayn Rand, Paul Ryan and Rand Paul have been mentioned before, in the title text of 1277: Ayn Random . That idea may have been the prototype for this. Connecting Marilyn Manson with Marilyn Monroe and Charles Manson is likely a tongue-in-cheek reference, as the musician's stage name was literally chosen in the same way as this. In at least one case it is not entirely clear who is being referred to: "John Kelly" most likely refers to Gen. John F. Kelly , Donald Trump's chief of staff, but the name is extremely common and could equally refer to any number of people . The number # refers to the numbers on this numbered picture . Read more on this page: 1970: Name Dominoes/Numbered images . Wiki links not tested as they were set in only from the name in the comic. [This comic a large grid, 27 units wide and 35 units high, with 271 black "domino" tiles. On each tile there is a name written with white text. The grid is arranged so that each touching side corresponds with the first or last name of another person. Some of the domino tiles are rotated 90, 180 or 270 degrees so the text is either to be read down, up-side down or up. The names on the tiles are listed here below in approximate reading order starting at top left.] Christian Campbell, Neve Campbell, Joe McCarthy, Eugene McCarthy, Gene Vincent, Gene Kelly, Kate Hudson, Rock Hudson, Gordon Brown, James Brown, Jon Brown, John Howard, Columbo, Chris Columbus, Christopher Columbus, Naomi Campbell, Joseph Campbell, Joseph Smith, Frank Vincent, John Kelly, Katherine Johnson, The Rock, Chris Rock, Chris Isaac, James Newton Howard, John Wayne, Howard Stern, Howard Hunt, Chris Hughes, Naomi Watts, Naomi Klein, Kevin Kline, Francis Bacon, Francis Drake, Lyndon Johnson, Oscar the Grouch, Oscar Isaac, Isaac Hayes, Isaac Newton, Wayne Newton, Wayne Knight, Helen Hunt, Helen Hughes, James Watt (Steam), James Watt (Interior), Kevin Costner, Kevin Bacon, Kevin Love, Lisa Frank, Frank Drake, Drake, Oscar de la Renta, Oscar de la Hoya, Sean Hayes, Wallace Shawn, Wayne Howard, Wayne Brady, James Brady, Tom Brady, Helen Thomas, Tom Hanks, Hank Aaron, Aaron Carter, Stephen James, Will Smith, Kevin Smith, Kein James, Garfield, James Garfield, Warren Buffett, Jimmy Buffett, Warren Beatty, Elizabeth Warren, Earl Warren, Eliabeth Kolbert, Stephen Colbert, George Wallace, Charles Wallace, James Monroe, Marilyn Monroe, Hank Williams, William C. Williams, Steve Harvey, Domino Harvey, Harvey Milk, James Saint James, Etta James, Jim Jones, James Earl Jones, Charlie Parker, Ray Parker Jr., Ray Charles, Charles Manson, Marilyn Manson, Robin Williams, Billy D. Williams, Will Wright, Fats Domino, Bill Clinton, Jimmy John, Tom Jones, Tommy John, Quincy Jones, James Earl Ray, Man Ray, Rachel Ray, Ray Allen, Tim Allen, Tim Cook, Tim Howard, Robin Wright, Wilbur Wright, Fatty Arbuckle, Fat Joe, George Clinton, John Kerry, Kerry Washington, John Irving, John Quincy Adams, John Adams, Amy Adams, Aimee Mann, Superman, Batman, Ayn Rand, Lily Allen, Paul Allen, Ron Howard, Howard Hughes, Joe Kennedy, George Bush, George Wasington, Wasington Irving, Martha Wasington, Ma Rainey, Jack Ma, Super Grover, Jack Black, Rand Paul, Paul Ryan, Paul Simon, Ron Paul, John Hughes, Langston Hughes, John F. Kennedy, Little Richard, Rich Little, Martha Stewart, Yo Yo Ma, Ma Bell, Grover Cleveland Alexander, Grover Cleveland, Jack White, Jack Ryan, Debby Ryan, Carly Simon, Carly Hughes, Charles Evans Hughes, John Williams, Little John, Stuart Little, Potter Stewart, Kristen Stewart, Kristen Bell, Kristen Hooks, Alexander Graham Bell, Franklin Graham, Lloyd Alexander, Meg White, Meg ryan, Debbie Reynolds, John Reynolds, Carly Fiorina, Grace Lee Boggs, Wade Boggs, William Safire, Prince William, Little Prince, Harry Potter, James Potter, James Hook, James Dean, Aretha Franklin, Frank Lloyd Wright, Barry White, Walter White, Walt Whitman, John Kelly, Grace Lee, Nancy Grace, Garnet, Prince, Prince Fielder, Prince Harry, Harry Styles, John Dean, Benjamin Franklin, Harrold Lloyd, Harrold Ford, Betty White, Meg Whitman, Christine Todd Whitman, Megyn Kelly, Grace Kelly, Grace Jones, Jack Nicholson, Jack Ruby, Jack Russel, Harry Fielder, Harry Trueman, Harry Jon Benjamin, John Edward, Benjamin Harrison, Harrison Ford, Henry Ford, Betty Ford, Betty Friedan, Chris Christie, Chris Pratt, Maggie Grace, Grace Hopper, Russel Crowe, Russ Smith, John Smith, Justin Long, John Bel Edwards, John Candy, John Henry, Henry James, Bill James, Chirs Cooper, Chirs Hemsworth, Chirs Evans, Topher Grace, Van Morrison, Sheryl Crow, Sheryl Sandberg, Cameron Crow, Long John Silver, Olivia Newton John, Huey long, John Edwards, Candy Crowley, Alestier Crowley, James Fenimore Cooper, James Cook, Robert Frost, Bob Evans, Evan Tayler Jones, Van Jones, James Cameron, Cam Newton, Cameron Diaz, Huey Newton, Huey Lewis, John Lewis, Jenny Lewis, Ryan Lewis, Burt Reynolds, Alistiar Cooke, Alistair Cookie, Cokie Roberts, John Roberts, Robert Johnson, Robert E. Lee, Tommy Lee, Tommy Lee Jones, Etta James, John Oliver, Ryan Reynolds, Alastair Reynolds

Personal Data

Personal Data

https://www.xkcd.com/1971

https://www.explainxkcd.com/wiki/index.php/1971:_Personal_Data

[Cueball is talking to Ponytail and White Hat. Both of them are looking at Cueball.] Cueball: Everyone keeps talking about "personal data." To be honest, I don't really know what it is . Cueball: I mean, I understand the idea and know it's a thing I should protect. But it's so... abstract. [Close-up on Ponytail.] Ponytail: Yeah. Ponytail: It's like "the economy." I don't really know what the economy is, if we're getting specific. I know stocks going up is good. For people who own stocks, at least. Ponytail: Whatever "stocks" are. [White Hat responds with his arms slightly out and palms open. Both Ponytail and Cueball are looking at him.] White Hat: Yeah, or taxes. Everyone talks about taxes. What are they? Do I have to pay them? And to who? Cueball: OK, wait, you definitely need to learn about that one. Ponytail: Yeah, ideally sometime in the next few weeks.

This is another comic poking fun at adults who have trouble dealing with grown-up issues. The comic starts with Cueball wondering what " personal data " is, saying he doesn't understand what it is, and it is an abstract concept. Ponytail follows by pointing out she doesn't understand what " the economy " is, and conjecturing that it is related to " stocks ", although admitting that she also does not understand what stocks are. The punchline comes when White Hat says that he doesn't understand what " taxes " are and asks if he really has to pay them and to whom. This surprises Cueball and Ponytail, who promptly advise him to learn about that one soon. The title text has White Hat asking another series of tax-related questions that adults are expected to know already, further compounding his troubles. See details on these four difficult topics below. The joke is that White Hat has mistakenly associated taxes with the economy and personal data as "grown-up" topics which are too confusing to fully grasp. Like the other two topics, taxes are a complex issue which many adults don't fully understand and have a vague sense that they should know more about or interact with. However, most people can remain passively ignorant about the significance of the economy or personal data without it disrupting their lives; this is not true of taxes, which people must actively pay and file annually or suffer financial and possibly criminal penalties. White Hat not knowing what taxes are indicates that he may not have paid his taxes in previous years, which would be alarming since tax evasion is punishable as a crime. Ponytail's remark that he should do this ideally in the next few weeks is referring to this year's US Tax Day which falls on April 17, 2018, less than four weeks after the release of this comic. So if you do not have your tax preparation under control, it is time to research how it works now. This is not the first time Randall has made a comic about people having trouble understanding the US tax system in relation to an approaching tax day. Other instances include the title text of 1805: Unpublished Discoveries from March the year before this comic, and this one from August 2015: 1566: Board Game . This comic references several advanced topics that people commonly talk about, but may not actually understand well: Personal data is usually thought of as any information that pertains to a private person. But this definition is very vague and can encompass a huge variety of data ranging from very sensitive (Social Security number, bank account details, passwords) to less sensitive (first name, color of pet cat). Different people also have different ideas of what information is considered sensitive. For example, some may want eagerly to share the location of their weekend activity with the world, whereas others may prefer not to let everyone know their location. Even though it is generally advised to keep personal data private and not to expose it to the public or to companies (especially online, e.g. Facebook and Google), not everyone agrees on the level of privacy that should be afforded to the data. Some hold the view that even innocent-looking personal data can be harvested and used for unsavory purposes (for example, a health insurance company can use social media posts about eating fast food as a cause to raise premiums, or a government can use cat pictures as evidence of pet ownership and demand license fees), and therefore all personal data should be strictly controlled. Others hold the view that sometimes it is worth exchanging some degree of privacy for other conveniences (for example, meeting friends by sharing their location info or getting cheaper prices from targeted advertising based on web browsing history). Personal data breaches were in the news a few days before the publishing of this comic when the UK's Channel Four released an investigative documentary about political consulting firm Cambridge Analytica. Among the revelations of the documentary were that the company had used Facebook to not only harvest the personal data of users taking their polls, but the friends and family of those users, without their knowledge or consent. They used this information to attempt to influence both the 2016 United States presidential election and the UK's Brexit vote . This sparked an ongoing discussion about the security of personal data and the role of social media in securing it. Such data breaches has been the topic of at least one previous comic: 1286: Encryptic . Technological changes in the past few decades have made personal data much easier to collect, share, and analyze in bulk, raising new questions and concerns that have not been considered before. Even people who can define what data is personal to them may not realize the full extent of how others might use it, or how it impacts their lives. The economy, at a basic level, is the circulation of money which enables productivity. For example, a bus driver might use their money to watch a movie, the movie producer might use their revenue (gathered from the bus driver and many others) to purchase editing software, the software maker might use their revenue (from the movie producer and others) to buy food, and the food producer might use that money to take a bus, thus returning the money back to the bus driver. The total amount of money has not changed, it merely circulated in a loop, but everyone in the loop received benefits and produced value in the form of goods or services. The real world economy has much larger and more complex networks of buyers and producers compared to the example above, but nevertheless it works on the same principle. Many people correctly associate the economy with money (or stocks in Ponytail's case), but may not understand the full picture. Circulation of money is critical to a healthy economy. In a recession, financial hardship causes people to spend less money, which leads to fewer goods being produced, fewer jobs available, and people earning and spending even less money. That is why (somewhat counter-intuitively) governments need to spend more money during a recession in order to infuse money back into the economy and get it circulating again. The Federal Reserve lowering interest rates is also a planned, strategic move to increase the money supply, which encourages investment and economic growth. Randall made a comic where stock and economy was an integral part of the largest of the panels: 980: Money Stocks in this context refers to companies listed on public stock exchanges, in which investors can buy and sell an economic stake, or share of the company's ownership. Companies offer stocks as a way to raise funds for its operation and expansion, selling off partial ownership of the company in exchange for cash. Investors mainly trade stocks for financial gain as well, collecting part of the company's profits as dividends and potentially selling the same shares at a higher price later. The value of stocks depends on a subjective valuation of the company. Stock price generally rises if the company is doing well and investors expect it to keep growing and make more profit. It generally falls if the company is doing poorly and investors don't see a brighter future. However, it is also influenced easily by external factors like political climate, release of (mis-)information, or even investors' mood. It is very hard even for experts to predict stock price movements accurately. This is why scientists should not think they can figure out the stock market, which was the topic of this comic: 1570: Engineer Syllogism . Through pension funds, mutual funds and other investment vehicles, a large portion of the population of developed countries have an indirect stake in the success (or otherwise) of many of the businesses that make up a significant element of the economy (see above). An economy that is experiencing healthy growth would generally see the value of those businesses increase, and that is reflected in the value at which investors would be willing to buy and sell those shares. So a growing economy would tend to associated with rising stock prices. In the past, stock ownership has been tracked using paper certificates which owners can hold and store, like cash. Nowadays most stock transactions are performed electronically and no physical items are sent. The intangibility of shares and volatility in price makes stocks feel like only a virtual concept that can be hard to grasp. Taxes are money that governments collect from people under their jurisdiction in order to fund government agencies providing public services. To answer White Hat's other questions (including the ones in the title text): While the concept of paying taxes is simple, the processing of filling out the paperwork is often complex and laborious. This is because the calculations leading to the final tax amount needs to take many many factors into account: ... and much more. Many people would not be familiar enough with the tax code to be able to do all their paperwork alone. [Cueball is talking to Ponytail and White Hat. Both of them are looking at Cueball.] Cueball: Everyone keeps talking about "personal data." To be honest, I don't really know what it is . Cueball: I mean, I understand the idea and know it's a thing I should protect. But it's so... abstract. [Close-up on Ponytail.] Ponytail: Yeah. Ponytail: It's like "the economy." I don't really know what the economy is, if we're getting specific. I know stocks going up is good. For people who own stocks, at least. Ponytail: Whatever "stocks" are. [White Hat responds with his arms slightly out and palms open. Both Ponytail and Cueball are looking at him.] White Hat: Yeah, or taxes. Everyone talks about taxes. What are they? Do I have to pay them? And to who? Cueball: OK, wait, you definitely need to learn about that one. Ponytail: Yeah, ideally sometime in the next few weeks.

Autogyros

Autogyros

https://www.xkcd.com/1972

https://www.explainxkcd.com/wiki/index.php/1972:_Autogyros

[A picture of Megan wearing aviator goggles, sitting in an autogyro and holding the control stick. The autogyro is surrounded by sentence fragments, explaining its characteristics. The one above the blade that concerns the blade has an arrow pointing from the text to the blade. The sentences in columns from the left (i.e. first four sentences to the left, then two above the autogyro's body, and finally six sentences to the right):] Looks like a helicopter, but is nothing like a helicopter Flies like a plane but is nothing like a plane Sort of like a powered parachute Rare in the US, usually homemade. Common in Europe. Big blade on top is not powered and spins freely Can often be flown without a license Cheap Needs a runway to take off, but not a long one Can land vertically Cannot hover Never stalls Extremely safe, unless you do the one thing you instinctively do to escape a stall in a normal airplane, in which case it will crash immediately. [Caption below the panel:] Autogyros are weird .

Randall has been looking at the facts about autogyros , hence the title of the comic. He has drawn Megan flying in such a vehicle with several statements of the facts he has unveiled. Randall states that an autogyro is nothing like a helicopter (which it looks like), nothing like a plane (but flies like one) and works like a powered parachute or paraplane (which it might kind of look like except without a parachute). He continues to make a total of 12 statements which will be explained individually below. The final statement at the bottom right is the punch line of how strange these flying machines are, because they are safe, as long as you do not do what a pilot instinctively would do in a plane in case of a stall because if you do so the autogyros will crash immediately... See the explanation below . That sentence is almost rendered unnecessary by the one above it that states that autogyros never stalls ! Randall's conclusion is clear: Autogyros are weird . In the title text Randall continues on the last statement by saying that today, autogyros are much more stable. Which, presumably, must refer to how this was not always the case. This new stability, then, probably means that a stall situation is much less likely and the last statement is not really all that relevant. Randall then goes on to suggest that the autogyro people will be angered by this comic, which attacks the safety of their beloved machines. But he keeps on mocking them, stating that they will come after him, once they have finished building the autogyros they have been working on in their garages for the last 10 years. By this, he implies that the people who work on them do this as a home garage project, so they will never really be able to finish or fly them. "Looks like a helicopter, but is nothing like a helicopter" It is like a helicopter in the sense that a horizontally spinning fan provides the lift. It is unlike a helicopter because A) the fan is not powered, B) the fan does not provide forward propulsion, C) it is incapable of hovering, or moving in any other direction than forward. "Flies like a plane but is nothing like a plane" Its flight pattern resembles a plane in that it can only move forward, turns by banking, and needs to maintain forward velocity in order to climb. However, unlike a plane, it can only maintain control when the rotor is loaded in the normal direction. Airplanes are "ok" when upside down, or when there's no load on the lifting surfaces. Autogyros lose control, much like a parachute under those circumstances. "Sort of like a powered parachute" A powered parachute , also referred to as a PPC or paraplane, is a similar design except instead of a freely-rotating blade they are attached to a large parachute that acts like an airplane wing. As long as there is thrust the parachute will fill with air and maintain its wing-like characteristics, with the advantage of acting like a real parachute in the event of a loss of thrust (i.e. engine dies) wherein they come floating down at a speed significantly slower and more survivable than freefall. A single-seater can often be flown without a license and can be as inexpensive as $5,000 USD in parts. "Rare in the US, usually homemade. Common in Europe." Autogyros are uncommon in the US because of the light sport rule (there is nothing on autogyros), while there is a detailed section in the European version of the light sport rule so they would obviously be more common in Europe. "Big blade on top is not powered and spins freely" The blades rotate due to the wind. Some autogyros use power to rotate the blade to speed before take-off but the power is removed for flight. "Can often be flown without a license" Autogyros are frequently built as ultralights , and that group of aircraft are a special case where licenses are not needed. ( In the US , ultralights are aircraft that weigh less than 254lbs, carry less than 5 gallons of fuel, stall at less than 24kts, have a maximum speed of less than 55kts, and carry only the pilot.) "Cheap" Helicopters are notorious for being extremely expensive to operate. At a typical general aviation service in the US, a two-seat aircraft may rent for under $100/hr, while a helicopter runs over $200/hr. Similarly, a small used helicopter may cost almost $200,000 while a small new autogyro may cost under $25,000. Since many people home-build their autogyros, it would often be even cheaper. "Needs a runway to take off, but not a long one" An autogyro must be moving forward relative to airspeed in order for the rotor to generate lift. It needs a runway to take off, but with the extra lift provided by the rotors, the runway can be much shorter than a regular one. "Can land vertically" An autogyro can land vertically: for that matter, so can any airplane. What matters isn't ground speed but airspeed, and as long as there's as much headwind as the landing airspeed of the aircraft, it will land vertically. Now, with fixed-wing airplanes, the landing speed is at least 40-50 mph, and you don't often find headwinds like that. The much lower landing airspeed of an autogyro makes vertical landings feasible. "Cannot hover" True hovering would require the rotor to be powered. However, an autogyro must be moving forward relative to airspeed in order for the rotor to generate lift. "Never stalls" Most conditions that would cause a stall in a fixed-wing airplane such as low speeds, high-G maneuvers, and gusty winds don't apply to autogyros. The rotor in an autogyro is in equilibrium, the inner, slower part is stalled, the middle part makes it spin and the outer, faster part slows down the rotor and provides lift. As the angle of attack increases, a fixed-wing aircraft would stall, however, on an autogyro, it will just make the lift-generating area smaller, causing the rotor to automatically spin faster and the equilibrium is restored. This is not entirely correct, however. If you reduce the forward speed of an autogyro, the rotor slows down, reducing lift so the autogyro will descend. Under most circumstances, this would lead to a controlled landing. However, if it happens at a high altitude, you can run out of lift completely while still high above the ground causing a stall. This is more likely to happen if there is a strong tailwind. "Extremely safe, unless you do the one thing you instinctively do to escape a stall in a normal airplane, in which case it will crash immediately." Autogyros are considered safe due to their slow landing speed, which is important in emergency landings, their forgiving behavior in windy conditions, and the fact they are almost impossible to stall. This is thanks to the freely spinning rotor. Unfortunately, as soon as the rotor stops spinning, the whole aircraft falls like a brick and the rotor may be impossible to restart in flight. This is a situation that should be avoided at all costs. Normally it is not a problem since the weight of the aircraft keeps the rotor spinning. However, if the weight becomes too low or even negative, the angle of attack will become negative, and the rotor will slow down and eventually stop. It can happen when the pilot "pushes on the stick" and dives. Unfortunately, "pushing on the stick" is also how you escape a stall in a fixed-wing (normal) airplane as it is a way to regain airspeed. This is actually a counter-intuitive maneuver but because a stall is an emergency, pilots are trained to do it instinctively. It can trick a pilot trained in fixed-wing aircraft into doing the one thing that shouldn't be done on a gyro. [A picture of Megan wearing aviator goggles, sitting in an autogyro and holding the control stick. The autogyro is surrounded by sentence fragments, explaining its characteristics. The one above the blade that concerns the blade has an arrow pointing from the text to the blade. The sentences in columns from the left (i.e. first four sentences to the left, then two above the autogyro's body, and finally six sentences to the right):] Looks like a helicopter, but is nothing like a helicopter Flies like a plane but is nothing like a plane Sort of like a powered parachute Rare in the US, usually homemade. Common in Europe. Big blade on top is not powered and spins freely Can often be flown without a license Cheap Needs a runway to take off, but not a long one Can land vertically Cannot hover Never stalls Extremely safe, unless you do the one thing you instinctively do to escape a stall in a normal airplane, in which case it will crash immediately. [Caption below the panel:] Autogyros are weird .

Star Lore

Star Lore

https://www.xkcd.com/1973

https://www.explainxkcd.com/wiki/index.php/1973:_Star_Lore

[A black panel with 31 dots of different sizes and in various colors (white, red, yellow, blue and green). These bright dots are scattered around three white speech bubbles for off-panel speakers. Next to the top left corner of the first bubble, there are five dots close together. Two white, two yellow (one brighter than the other) and a red dot that is clearly larger than any of the other four.] Person 1 (off panel): That cluster was known to the ancients as the Five Sisters. Person 1 (off panel): The red one is a supergiant and will probably explode within the next million years. Person 2 (off panel): Wow! [Caption below the panel:] There are too many status LEDs in my room.

Computers, chargers, and other electronic items often have status lights in various colors. In a dark room, these lights appear as pinpricks of light, similar to constellations. Presumably, Randall's room has many such items. This may be a My Hobby comic in the sense that his room doesn't really look like that, rather, he claims it does for humor value. It's also not clear whether this refers to Randall's bedroom (typical US usage of "my room" refers to one's bedroom) or some other room Randall spends a good deal of time in. However, since a bedroom is generally the only room in which one might spend significant time in the dark, it seems very likely this is referring to Randall's bedroom. The comic's narrator is explaining how some of his lights remind him of stars, which gives him an opportunity to show off his knowledge of sci-fi trivia: "The Five Sisters" could be a reference to a pentagon-shaped constellation from Isaac Asimov's book Foundation's Edge , though it could not have been 'known to the ancients' since it was less than 100 years old; though it could also be a somewhat more oblique reference to the Pleiades cluster (often called the Seven Sisters). It could also refer to the cluster of 5 lights next to the speech bubble, which is reinforced by the next bubble talking specifically about the bigger red light in the cluster. Interestingly, there are some green stars. Stars might look green due to a neighbouring star, but green stars are actually impossible due to the principle of black body radiation. Green status lights on electronics are common, however. [ citation needed ] In the title text, the narrator describes his smoke alarm status light as a pulsing variable star. A smoke alarm is a device that detects smoke, which would indicate a fire. These are commonly placed in houses as a safety precaution. Typically, many smoke alarms have a status light that blinks to assure that they are still functioning. A subtle blinking light is more clear in its (intermittent) activation than a steady one that might actually be inactive but reflecting external illumination, while a high-intensity photoemitter capable of being seen in near-direct daylight would be annoyingly bright when the lights are off at night. [A black panel with 31 dots of different sizes and in various colors (white, red, yellow, blue and green). These bright dots are scattered around three white speech bubbles for off-panel speakers. Next to the top left corner of the first bubble, there are five dots close together. Two white, two yellow (one brighter than the other) and a red dot that is clearly larger than any of the other four.] Person 1 (off panel): That cluster was known to the ancients as the Five Sisters. Person 1 (off panel): The red one is a supergiant and will probably explode within the next million years. Person 2 (off panel): Wow! [Caption below the panel:] There are too many status LEDs in my room.

Conversational Dynamics

Conversational Dynamics

https://www.xkcd.com/1974

https://www.explainxkcd.com/wiki/index.php/1974:_Conversational_Dynamics

[Cueball is sitting at a computer and pointing at the CRT monitor. White Hat is standing behind him.] Cueball: Check it out! My new system allows anyone on Earth to inject themselves into any conversation happening anywhere  at any time. White Hat: Cool! I bet this won't lead to any unhealthy dynamics! [Caption under the panel:] The creation of the modern web

On the modern World Wide Web (usually coined as Web 2.0 , in contrast to the original web envisioned and created by Tim Berners-Lee ), particularly on internet forums (like the xkcd forums ), a pervasive issue is that forum users with strong opinions but little interest in fruitful discussion will often interject themselves into all conversations that are related to their area of interest; examples include conspiracy theorists , political extremists , and trolls . This counterproductive behavior is not feasible in real life, where conversations happen locally and synchronously and one must be physically present in order to participate. In this sense, it is enabled by Internet forum technology. In forums that have search features, it is even easier for these problematic users to identify and target large numbers of threads rapidly. The field of conversational dynamics studies the interpersonal processes underlying dialog between people, and this is an example of how changing the mode of communication can negatively impact productive "conversational dynamics" (hence the title). In this satirical comic, Randall imagines the inventor of the modern web, here depicted as Cueball , correctly anticipating that anyone will be able to inject their opinion into any conversation. When he tells White Hat about it, White Hat's comment, either sarcastic or very naive, interprets this as a benefit as he is willing to bet that this will not lead to any unhealthy [conversational] dynamics . In the best case, naive scenario, the web enables broader participation by helpful users with relevant information, in the real world it rather turned out as a potential problem as described above with trolls and conspirators overtaking many online forums. Note that in contrast to what the comic depicts, there is no single person or group who created the foundation of the modern web, unlike the original web where there is an identifiable person. In the title text, White Hat suggests to Cueball to add a search feature that will enable these "helpful" users to be even more helpful by enabling them to jump into not just one conversation at a time, but into hundreds of conversations simultaneously. This may be referring to free, anonymous chat sites like 4Chan or possibly Discord . Whether White Hat is again sarcastic or just even more naive, Cueball immediately jumps to the conclusion that this will be an even better idea than his own, and continues to envision a system where "only the most well-informed people with the most critical information to share will use that feature." In reality, as any modern user of Internet forums would be aware, both of these technologies are routinely abused by problematic users, and the characters are being too optimistic. That we today need someone to fight online trolls was the subject of 591: Troll Slayer . [Cueball is sitting at a computer and pointing at the CRT monitor. White Hat is standing behind him.] Cueball: Check it out! My new system allows anyone on Earth to inject themselves into any conversation happening anywhere  at any time. White Hat: Cool! I bet this won't lead to any unhealthy dynamics! [Caption under the panel:] The creation of the modern web

Right Click

Right Click

https://www.xkcd.com/1975

https://www.explainxkcd.com/wiki/index.php/1975:_Right_Click

[Empty frame with Cueball standing slightly right of center.] [Caption below the frame:] Editor's Note: Today's comic is optimized for local viewing. To see the full version, just save a copy of the image!

This was the eighth April fools' comic released by Randall . The previous April Fool's comic was not from the year before as there was no such comic released in 2017 . Instead, the previous one was 1663: Garden , scheduled for released Friday, April 1st, 2016, but in the end released on Monday April 4th 2016. The next was 2131: Emojidome released on Monday, April 1st, 2019. This comic was released on April 1 even though that was a Sunday (only the fourth comic to be released on a Sunday). But it was only due to the April Fool joke, as it did replace the comic that would have been scheduled for Monday, April 2nd. The next comic, 1976: Friendly Questions , was first released on Wednesday, April 4th. At first, the comic seems like the most simplistic xkcd comic possible - Cueball standing and doing nothing. The "editor's note" tells you to save a copy of the image to "view the full comic". To save an image from a browser most people would right-click on it (or long-click in mobile devices) which normally leads to a "context menu" allowing several actions related to the image, including saving/downloading. This is what you are encouraged to do by the editorial note as well as by the comic name and title text. However, the context menu opened is not the default context menu of the browser but an elaborate context menu containing many nonsensical options. At first it also seems impossible to save the image using that menu. However, after exploring the context menu you can find an "easter egg" in one of two different places (see below) which unlocks the save option. This save option gives you a different image than the one you see, which can be thought of as "the full comic" although the meat of the comic is actually in the interactive context menu itself. Note that "cheating" by disabling JavaScript and other methods that allow you to directly save the image won't get you that "full comic" image. This comic pokes fun at how hard it can be to save an image or to just navigate context menus in some computer programs. The "easter egg hunt" might be related to the fact the comic was released during Easter (which fell on April fool's in 2018). It might also be related to the movie "Ready Player One" which was recently released when the comic was released. In the movie, based on the book by Cline, finding an "easter egg" in a VR world was a central plot point. The title is reminiscent of one of the first interactive comics 1110: Click and Drag , where the title explains what the user should do to experience it. However, that was not a fools' day comic. The comic uses JavaScript and HTML5 to override the standard context menu. Since modern browsers use the same features to integrate Add-ons into that menu, the behavior may be different depending on the browser environment. Browsers with JavaScript disabled, either totally or by using NoScript , won't access the functionality of the comic, but of course can easily save the image (not "the full version" but the image that is seen initially). The manipulated context menu is described below . Here all the spells from the "d&d" game are detailed, including the traits you need to enter to get to them and the link they lead to/effect they create. To get to a specific spell using this table you need to go to games->d&d->cast and then enter the traits - level, class, school, and components - in any order. Note that many spells list more than one class in the table (in d&d it means multiple classes can cast that spell), which means you need to choose one of those classes in the menu. Components are listed in the table as V for Verbal Components, S for Somatic Components and M for Material Components - choose "yes" or "no" for these based on whether the matching letter is there or not. The vast majority of spells (285 of them apparently) are actually links to xkcd comics, what ifs, or external pages that somehow demonstrate or relate to the spell. These 9 spells all appear with an arrow and open submenus when hovered on. The submenus are all actually from different parts of the context menu. Several of the spells are "teleportation/transportation" related which might explain why they lead you to a different place in the menu. These 10 spells activate different JavaScript functions that affect the page in various ways, permanent or temporary, that are suggestive of the spell that was cast. [Empty frame with Cueball standing slightly right of center.] [Caption below the frame:] Editor's Note: Today's comic is optimized for local viewing. To see the full version, just save a copy of the image!

Friendly Questions

Friendly Questions

https://www.xkcd.com/1976

https://www.explainxkcd.com/wiki/index.php/1976:_Friendly_Questions

[Cueball and Hairy meet each other.] Cueball: Hey! Hairy: Oh, hi! [Cueball looks down at a sticky note in his hand.] [The yellow sticky note reads:] Normal human conversation 1. Ask them about themselves [Cueball looks at Hairy.] Cueball: How many...apples...have you eaten? Hairy: ...Like, in my life? Cueball: Yes. Hairy: ... Cueball: ...I should go. Hairy: OK.

A common theme in xkcd is social awkwardness . Oftentimes Cueball / Randall will grossly overthink casual social interactions, such as small talk. In this comic, Cueball has prepared a note to himself, preparing for the said small talk with Hairy , but it ultimately backfires. This is very similar to the comic 1961: Interaction which came out just 5 weeks before this one. And a similar interaction between Cueball and Hairy occurs in 1917: How to Make Friends from less than half a year before this comic. In this comic, Cueball has prepared for a conversation with Hairy, by writing an instructional note for himself. The note tells him to start the conversation by asking some questions about the other person. In theory, this is perfectly good conversational advice; unfortunately, Cueball's understanding of social interactions is so abstract that he actually has no idea what questions to ask. He hastily improvises a question about the number of apples Hairy has eaten in his lifetime, which, although it does meet the criteria suggested by the note, is not a particularly interesting or meaningful question to ask someone. Cueball realizes from Hairy's reaction that he has made a mistake, and decides to abort the interaction. Normally, one would ask questions such as "How are you?" or "What have you been up to lately?", instead of asking random facts of someone else's life, such as "How many apples have you eaten in your life?" [ citation needed ] The title text continues to show the flaws in Cueball's approach to social interaction, which is very systematic: he seems to trying to create some kind of reproducible methodology that he can follow in order to carry out a conversation, unaware that conversations tend to be spontaneous and do not follow rigidly defined rules. Additionally, one of the main points of conversation is to gain some understanding of the other person; by focusing on the conversation itself , Cueball is denying the very purpose of the interaction. A slight side-joke is the list being numbered despite only containing one item, although this could imply that Cueball has other notes that he would have continued to refer to if the first one produced a successful result. The advice to "Ask them about themselves", specifically noted as the "first thing" after introducing yourself, was promoted to overcome society anxiety in the Periscope -based videocast of Scott Adams , creator of the Dilbert comic strip (see audio-only podcast [1] ). Given Randall's personality and previous professional vocation (working with nerds at NASA and in academia), it is highly likely he would be a fan of the strip and also the creator's related works such as Adams's blog, Twitter feed, and the like. The real coincidence is the videocast in question likely occurred just a day before this comic was published ; the audio was published the same day as the comic and usually delays the video by a day. [Cueball and Hairy meet each other.] Cueball: Hey! Hairy: Oh, hi! [Cueball looks down at a sticky note in his hand.] [The yellow sticky note reads:] Normal human conversation 1. Ask them about themselves [Cueball looks at Hairy.] Cueball: How many...apples...have you eaten? Hairy: ...Like, in my life? Cueball: Yes. Hairy: ... Cueball: ...I should go. Hairy: OK.

Paperwork

Paperwork

https://www.xkcd.com/1977

https://www.explainxkcd.com/wiki/index.php/1977:_Paperwork

[Cueball holds his smartphone in both hands and takes a picture of his desk which has several sheets of paper (with unreadable text) lying around on it, hanging out over the edge of the table and also on top of his laptop standing on it. A more than half empty glass of water stands behind the laptop. The shutter sound is shown with small dots around it to indicate the picture is just being taken now.] Phone: Click [A smaller frame is inside the main frame to the right. It shows Cueball now typing on his phone. Above the frame a "speech" box goes outside the smaller frame but points with a jagged arrow towards the phone. Inside this box Cueball's message is displayed. At the bottom two typical social media buttons are shown, the left of them is grayed out, with gray text inside a thin gray line, the right button has dark text on a dark gray background with a solid black line around, probably to indicate that Cueball has pushed this right button at this very moment.] Ugh, check out how much tax paperwork I have to do. Cancel Post [Caption below the panel:] I've accidentally discovered the world's most efficient way to leak personal information.

Cueball is complaining on social media about how much tax paperwork he has to do. He posts a picture of all his tax documents to share how much work he had to do before Tax Day . At first this just seems like an innocuous and generic thing people post on social media, but then the caption gives us a sobering reminder (and punchline): Tax documents contain many specific and important personal information in a very small area, like your social security number, address, income etc, and Cueball has just posted all of them for identity thieves to just stumble upon. It is generally a bad idea to give out personal information like this to anyone, especially people online as this data can be used in many forms of fraud, by people pretending to be you or even using your login to gain access to your bank or other private matters. A picture of this information-dense tax return is the "most efficient" way to leak this critical data short of sending out the actual return. Lots of people take photos of themselves, others, and objects around them, and post them in public and semi-public places, often without fully thinking about the kinds of personal information they might be accidentally including. Even if they do examine the photo for personal information and conclude the photo is safe to post, information they think is innocuous might end up being meaningful to someone else, possibly in combination with other public information they might have gathered about a person. One example of a photo revealing more than was expected is when the Washington Post posted a picture of the TSA master keys . The photo was detailed enough that people were able to create and 3D print their own working keys. The title text further adds to the issues. First, it explains the picture was geotagged , which means anyone could easily find Cueball's home. Next, it also says his password manager was on his laptop screen, unlocked and presumably showing many of his passwords, usernames, and other information needed to log in to his accounts (such as email, banking sites, social media sites, etc.), thus allowing anyone to easily get in. Finally, the title text suggests Cueball's naked body was reflected off the laptop screen, and inadvertently included in the picture. Thus the people wishing to use his information can now potentially blackmail him with this nude picture as well on top of anything else. With xkcd's stick figures it's usually impossible to tell if they are clothed or naked, but now that we know Cueball is naked in this one it may make this strip NSFW . Thus consider yourself warned. The nakedness of xkcd stick figures have been mentioned before – for instance, in the third strip of 566: Matrix Revisited , and in 864: Flying Cars where Megan is pictured topless. Having a picture of oneself naked on the internet, without your own intent or consent, is also generally a bad idea. Many young people (kids) find out when they send a nude picture to a boyfriend/girlfriend over Snapchat that it can be screenshotted. This prevents it from being removed later. And if/when they then fall out of love it might be shared online. Although illegal, this happens often, and causes harm to both the victim (who has been humilated online) and the offender (who can be jailed for this; it is considered child pornography if the nude person is underage). Both the United States and the United Kingdom have important tax-related deadlines in April, the month this comic was released. In the United States, the 2018 Tax Day fell on April 17, and in the United Kingdom April 6 is the start of the tax year . Taxes were also the topic of the comic 1971: Personal Data which was released just two weeks before this comic. [Cueball holds his smartphone in both hands and takes a picture of his desk which has several sheets of paper (with unreadable text) lying around on it, hanging out over the edge of the table and also on top of his laptop standing on it. A more than half empty glass of water stands behind the laptop. The shutter sound is shown with small dots around it to indicate the picture is just being taken now.] Phone: Click [A smaller frame is inside the main frame to the right. It shows Cueball now typing on his phone. Above the frame a "speech" box goes outside the smaller frame but points with a jagged arrow towards the phone. Inside this box Cueball's message is displayed. At the bottom two typical social media buttons are shown, the left of them is grayed out, with gray text inside a thin gray line, the right button has dark text on a dark gray background with a solid black line around, probably to indicate that Cueball has pushed this right button at this very moment.] Ugh, check out how much tax paperwork I have to do. Cancel Post [Caption below the panel:] I've accidentally discovered the world's most efficient way to leak personal information.

Congressional Testimony

Congressional Testimony

https://www.xkcd.com/1978

https://www.explainxkcd.com/wiki/index.php/1978:_Congressional_Testimony

[Megan and Cueball sitting against a leafless tree; they are on opposite sides.] Megan: Mark Zuckerberg is testifying before Congress this week. Cueball: Should be interesting. [Beat panel.] Megan: I recently re-watched Terminator . Cueball: Yeah? Megan: It's weird that the thing that evolved into Skynet wasn't our nuclear launch systems or our humanoid robots. Megan: It was the phone book where the Terminator looked up Sarah Connor's address. Cueball: Funny how things turn out.

Megan and Cueball are discussing Facebook CEO Mark Zuckerberg's upcoming testimony before Congress . The prepared testimony was released on the day this comic was released--see Congress releases Mark Zuckerberg's prepared testimony ahead of Wednesday's hearing . Facebook is facing questions on the Facebook–Cambridge Analytica data scandal involving the collection of personal information of up to 87 million Facebook users by the political targeting firm Cambridge Analytica. Megan then starts talking about re-watching The Terminator , a movie about a killer robot called "the Terminator" sent back in time by Skynet , a computer system that became self-aware (AI) and tried to kill off humans. The Terminator, played by Arnold Schwarzenegger , was sent back to try to kill the mother of the leader of the resistance before he was born. In the movie, the Terminator looked up the mother's name, Sarah Connor, in the phone book of a phone booth to find her address. Megan notices how strangely things have turned out in the real world. In the movie it was a nuclear launch system that turned on humans, building humanoid robots to hunt humans down; today, despite the fact that we have computer-controlled nuclear launch systems as well as humanoid robots, it was rather the modern version of said phone book that became our version of Skynet (Facebook). The computer program that tracks our information in a manner similar to a phone book was responsible for doing harm to its users by selling their information (and now it could be said to harm the people who created it, as well, since Zuckerberg is on trial). Cueball can only agree with her how funny things always turn out in retrospect. The title text makes the claim that James Cameron , who directed the first two films, was planning to make a third movie in the 1990s, which would have been the really prophetic one (i.e. the one that would have mirrored our present day most closely). Therefore, Skynet, having seen the result of this movie, wished to prevent the movie from ever being made, sending yet another robot back in time to prevent Cameron from directing it. Instead, Terminator 3: Rise of the Machines was released in 2003 and directed by Jonathan Mostow . Although Cameron is credited for writing it, he only created the characters. Since then three other movies have been made, all with different directors. [Megan and Cueball sitting against a leafless tree; they are on opposite sides.] Megan: Mark Zuckerberg is testifying before Congress this week. Cueball: Should be interesting. [Beat panel.] Megan: I recently re-watched Terminator . Cueball: Yeah? Megan: It's weird that the thing that evolved into Skynet wasn't our nuclear launch systems or our humanoid robots. Megan: It was the phone book where the Terminator looked up Sarah Connor's address. Cueball: Funny how things turn out.

History

History

https://www.xkcd.com/1979

https://www.explainxkcd.com/wiki/index.php/1979:_History

[In a small panel top left, Cueball walks up to Megan who is sitting on an office chair holding a tablet showing a screen full of (to the reader) unreadable text.] Megan: I read this article in an old newspaper, and I can't stop thinking about it. [Below is a large panel twice as wide as the first, and much longer. It contains the newspaper clip that Megan talks about. Three sections of the text is in normal black font, the rest is in gray font:] The public events of the last three months are of the class which will go into its permanent history. We have been living in an atmosphere of history which will be immortally preserved. Even the brief series of important dates to be collated for the use of the schoolboys of centuries hence will contain the day of the assassination, and the day of the death of President Garfield. The intermediate events co-related, like the defeat of Roscoe Conkling, will be of great interest, but will scarcely be likely to stand prominently out from the page of history written in 1881. To us who have been the witnesses, so to speak, of the tragic incidents of the times, it seems entirely probable that future generations will eagerly scan every feature of the recent bereavement which the nation has suffered. How accurately will future generations know the immense volume of grief and sorrow which has rolled over the land? Will those who come after us ever be able to understand the extent of our loss? Is there anything in the first century of our history—even the death of the great Lincoln—which can be used as a parallel? Perhaps a careful reading of the daily papers of the present. period may give some future antiquarian a fine idea of the feelings of the nation during the past summer. But these journals are so large, so full of detail, that we imagine the coming American will never find time to read the record. He must depend on a brief statement, meagerly compiled by some dry and tedious historian. —The Bloomington Daily Pantagraph September 30, th 1881 [The third and final panel is the same size as the first, below and to the right. It contains a zoom in on Cueball and Megan talking.] Cueball: Man. The past is so big . Megan: How do historians even cope? Cueball: I have no idea. Megan: I honestly have enough trouble just with the present.

This comic quotes a lengthy section of the Bloomington Daily Pantagraph's September 30, 1881 issue . The tragic event referenced throughout is the assassination of President James A. Garfield . Interestingly, the article is about how closely studied the incident will or will not be in the future. Garfield's assassination is rarely more than a quick note in a history class, leaving only the "dry and tedious" historians to comb through the details. The writer also notes that vast quantities of accounts exist of the national grief and trauma caused by Garfield's murder, and wonders whether students in the future will bother to read those accounts to understand it, or simply let historians sum it up without conveying the vastness of the response. That fear at least did prove well-founded; most students are not aware of the fallout of the assassination, or indeed, of Garfield at all. Cueball and Megan are discomfited by the fact there exists a vast, untapped store of information that they have never read, about an event they know little to nothing about despite it apparently causing nationwide trauma. This leads to a larger point about the vastness of history, and the impossibility of learning all of it. The article itself references other events that would have been in recent memory at the time of publication and draws some conclusions about which will be considered more important in the future. For example, it cites the defeat of Roscoe Conkling as a serious event that would fade in importance when compared to Garfield's assassination. Conkling was a senator in Garfield's party who resigned in protest of Garfield's policies assuming that he would easily win re-election by the state legislature--but then failed to achieve re-election due to party factions and political infighting. Interestingly a comparison of Google search frequency for the years 2004-2018 shows that Garfield is indeed searched for many times more often than Conkling. Conkling's failure to be re-elected by the New York state legislature, which seemed so vitally important at the time, is summarized by a brief two sentences near the bottom of Conkling's Wikipedia article and not even mentioned in the biography's summary. So the writer does appear to be correct that Conkling's re-election defeat was an episode that was of high importance as a current event that in the future was to become not much more than an obscure footnote. The writer speculates that there may not be any event in American history that matches the level of grief caused by Garfield's assassination, not even that of Lincoln. Here the writer is further off the mark, because in current historical memory, the Lincoln assassination is still a towering, defining event, whereas Garfield's is, comparatively speaking, a footnote. The bolded sections of the text emphasize some of the main points of the article for the modern reader and may also be another way Munroe makes the point that future readers are unlikely to have the patience to read lengthy, detailed explanations of past events. If they have time to pay attention at all, future readers will want the essence boiled down to a few major highlights. The title text indicates that there is more information about the past than can be researched by the manpower of available historians at this time. For whatever reason, be it lack of funding to carry out research or lack of interested people becoming historians, the facetious solution is to just ignore events of either even or odd numbered years. This would essentially halve the amount of data to go through and the amount of time to go through it, but it would be at the detriment of our understanding of all of the context of said events. As an example World War 2 started and ended on odd years, but some of the most tide-turning battles (Fall of France, most of Stalingrad, D-Day) happened on even years. Although this format with small panels above and below a larger one has been seen before, there could be an extra joke this time, if it is seen as if there were originally five panels to the comic, but the second and fourth (the even ones) were removed. [In a small panel top left, Cueball walks up to Megan who is sitting on an office chair holding a tablet showing a screen full of (to the reader) unreadable text.] Megan: I read this article in an old newspaper, and I can't stop thinking about it. [Below is a large panel twice as wide as the first, and much longer. It contains the newspaper clip that Megan talks about. Three sections of the text is in normal black font, the rest is in gray font:] The public events of the last three months are of the class which will go into its permanent history. We have been living in an atmosphere of history which will be immortally preserved. Even the brief series of important dates to be collated for the use of the schoolboys of centuries hence will contain the day of the assassination, and the day of the death of President Garfield. The intermediate events co-related, like the defeat of Roscoe Conkling, will be of great interest, but will scarcely be likely to stand prominently out from the page of history written in 1881. To us who have been the witnesses, so to speak, of the tragic incidents of the times, it seems entirely probable that future generations will eagerly scan every feature of the recent bereavement which the nation has suffered. How accurately will future generations know the immense volume of grief and sorrow which has rolled over the land? Will those who come after us ever be able to understand the extent of our loss? Is there anything in the first century of our history—even the death of the great Lincoln—which can be used as a parallel? Perhaps a careful reading of the daily papers of the present. period may give some future antiquarian a fine idea of the feelings of the nation during the past summer. But these journals are so large, so full of detail, that we imagine the coming American will never find time to read the record. He must depend on a brief statement, meagerly compiled by some dry and tedious historian. —The Bloomington Daily Pantagraph September 30, th 1881 [The third and final panel is the same size as the first, below and to the right. It contains a zoom in on Cueball and Megan talking.] Cueball: Man. The past is so big . Megan: How do historians even cope? Cueball: I have no idea. Megan: I honestly have enough trouble just with the present.

Turkish Delight

Turkish Delight

https://www.xkcd.com/1980

https://www.explainxkcd.com/wiki/index.php/1980:_Turkish_Delight

[A person wearing a cap, a fur coat, and gloves sits in a sled handing over a plate with small cubic pieces on it to a small boy with dark hair standing beneath. The boy reaches one hand to the plate.] Person in the sled: Have some Turkish delight. If you betray your family, there's more where that came from. [The boy tastes one piece.] [The boy looks at that piece.] [The boy looks up, to the direction where the gift came from, the piece still in his hands.] Boy: Wow. Boy: This is ... not great. [Caption below:] The Narnia books gave me a really unrealistic impression of how good Turkish delight tastes.

The Lion, the Witch and the Wardrobe is a fantasy novel by British novelist C. S. Lewis , the first published and best known of seven novels in The Chronicles of Narnia . In it, a group of four sibling children discover another world called Narnia. At the beginning of the story, the land is in a perpetual winter caused by the White Witch (the antagonist of the story). One of the children, Edmund Pevensie , is approached by the White Witch and offered Turkish delight , a type of confection, in exchange for leading the other children to her. What the book says and what the movie leaves out is he doesn't know the sweets are enchanted by the White Witch to make the eater want them the more they eat them. Not a full mind control, but more of a strong urge to get more. Turkish delight is very different from typical confections found in the modern Western world and isn't very popular in the United States. The primary flavoring agent of Turkish Delights, rosewater, has a strong perfume-like taste and is generally considered an acquired taste for western palates. Randall , who has made comics about being unimpressed by food in the past, comments that he was very disappointed when he tried Turkish delight, especially after having read in the novel about how delicious the characters considered it. If he were in Edmund's shoes, he would not have been persuaded. It is not uncommon for present-day Narnia fans to be disappointed when they try Turkish delight , as different as it is to modern confections. However, in the late Victorian era when Lewis grew up, Turkish delight was very popular in England . Because it was nearly impossible for local confectioners to make properly, it had to be imported from Turkey, at great expense, making it a status symbol for the wealthy and a rare treat for those with less money. When Lewis wanted to come up with the perfect temptation for Edmund, he drew on his own childhood memories of a favorite rare and expensive treat--which would have been even harder to come by because of sugar rationing during World War II , when the story was set. It also serves to emphasize how powerful the White Witch is for her to be able to offer such an expensive and hard-to-obtain treat so easily. Cinnabon (referenced in the title text) is a popular chain restaurant in the USA which serves mostly cinnamon buns covered in a thick, sugary glaze. The chain is not well known in Britain, but has recently opened a few restaurants , mainly in the London area. (A more common UK equivalent of the cinnamon bun is the Chelsea bun .) There are presumably no branches of Cinnabon in Narnia. [ citation needed ] Randall is saying that he finds cinnamon buns delicious, to the point where he would betray anyone for them. It should be noted that, in the books, it was Edmund who requested the Turkish Delight. Thus, had it been Randall instead of Edmund, he very well could have requested cinnabons. [A person wearing a cap, a fur coat, and gloves sits in a sled handing over a plate with small cubic pieces on it to a small boy with dark hair standing beneath. The boy reaches one hand to the plate.] Person in the sled: Have some Turkish delight. If you betray your family, there's more where that came from. [The boy tastes one piece.] [The boy looks at that piece.] [The boy looks up, to the direction where the gift came from, the piece still in his hands.] Boy: Wow. Boy: This is ... not great. [Caption below:] The Narnia books gave me a really unrealistic impression of how good Turkish delight tastes.

Rickrolling Anniversary

Rickrolling Anniversary

https://www.xkcd.com/1981

https://www.explainxkcd.com/wiki/index.php/1981:_Rickrolling_Anniversary

[Cueball and Megan are walking.] Cueball: This month marks ten years since the peak of the Rickrolling phenomenon. [In a frame-less panel they keep walking.] Megan: Seriously? Megan: Wow. Happy anniversary, I guess. [They keep walking silently, beat panel.] [And they walk on.] Cueball: We've known each other for so long. Megan: We really have.

Cueball tells Megan that by the release of this comic in April 2018 it is the 10th anniversary of the peak of rickrolling , and she is amazed that this has been so long ago. She then expresses a half-hearted happy anniversary wish, though it's not clear whether the anniversary she is congratulating is the phenomena itself having reached 10 years, or if she and Cueball met 10 years ago, coinciding with the height of the popularity of rickrolling, and this is reminding her to wish him a happy anniversary. After a beat panel Cueball concludes "We've known each other for so long", which is both a poetic affirmation of his friendship with Megan, and a line from the song " Never Gonna Give You Up ," the hit song by Rick Astley on which rickrolling is based. The first reference to rickrolling in xkcd was in 351: Trolling from 2007, where Astley himself was Rickrolled by Black Hat . Black Hat then later uses Astley to show his girlfriend Danish how Rick rolls in 524: Party , a New Year party from the end of 2008. Rickrolling had first started in 2007, but reached a peak in about April 2008 when, as an April fool's day prank, Youtube linked all its featured videos to Never Gonna Give You Up , and the New York Mets were Rickrolled by a public vote to choose a song for the 8th innings sing-song. This coincided with a sharp peak in searches for "Rick Astley" and related terms. The title text refers to another old xkcd meme of giving snippets of information to the reader that make them feel old . Although comics such as 218: Nintendo Surgeon in 2007 refer to facts that could make you feel old, the first comic directly build around factoids to make one feel old in xkcd was 891: Movie Ages in April 2011. This was 7 years before the time of publishing. The Bush Kerry election was in November 2004, 6½ years before that comic, making the title text statement that the beginning of this meme is closer to that election that today. This is the way most of these make you feel old comics are built. [Cueball and Megan are walking.] Cueball: This month marks ten years since the peak of the Rickrolling phenomenon. [In a frame-less panel they keep walking.] Megan: Seriously? Megan: Wow. Happy anniversary, I guess. [They keep walking silently, beat panel.] [And they walk on.] Cueball: We've known each other for so long. Megan: We really have.

Evangelism

Evangelism

https://www.xkcd.com/1982

https://www.explainxkcd.com/wiki/index.php/1982:_Evangelism

[A chart is shown with a line drawn from left to right with five markers on it. Each marker has a line going to it from a labeled below the main line. Above this there is a title and right below that a label above an arrow pointing to the right.] People by intensity of evangelism More intense Religious proselytizers People who want the US to switch to metric People who want the US to switch to metric but keep Fahrenheit People who threw away their socks and bought all one kind People who open bananas from the other end

In this comic, Randall presents a line plot where causes are listed, in increasing order, by the intensity of the evangelism of their advocates. Evangelism , in Christianity , is the commitment to or act of publicly preaching of the Gospel with the intention of spreading the message and teachings of Jesus Christ. “Evangelism” is also defined as any zealous advocacy for a cause, religious or not. The first punchline is that religious proselytizers are unexpectedly much less intense than advocates for such things as opening bananas from the other end—which is also the subject of the title text. The comic’s release date on April 18th, is likely correlated with this days assignment as the official “Banana Day” in the US. (However, at the time of release of this comic, this day was not mentioned on the Wikipedia list of food days in the US ). As the graph moves from left to right, the issues at stake have less and less impact on the life of someone who “converts”, but the intensity and fervor of those spreading the cause increases. This is counterintuitive, which is the joke. Below, each of the points on the chart, as well as the title text, is discussed. Religious proselytizers Religious proselytizers are the best known evangelists, and the term “evangelism” originally applied only to them. Christian faith remains roughly as popular as ever, but Christian evangelism has become less common and less accepted in the public sphere in recent decades, and often only practiced in specific venues. Randall contrasts them in this strip with four other groups which he finds to be more intense in their “evangelism”. People who want the US to switch to metric Unlike most of the world, the US uses US Customary units instead of metric units . The vast majority of the world population (and even some within the US) wish for the US to change, to the point that the US Congress already passed the Metric Conversion Act that U.S. President Gerald Ford signed into law on December 23, 1975. Though the US now uses SI units in many areas, especially professionally, most Americans deal more with US Customary units in their day-to-day lives. Randall has made a conversion chart for helping US people with the confusing metric units: 526: Converting to Metric . People who want the US to switch to metric but keep Fahrenheit Pro-metric people who wish to keep the Fahrenheit scale rather than change to Celsius are ranked as slightly more evangelic. A common argument for keeping the Fahrenheit scale is due to 0°F equating to “really cold” and 100°F to “really hot” when talking about weather. Fahrenheit also has smaller degrees than Celsius, so temperatures can be cited more precisely, if necessary, without the need to include fractional degrees. This also gives Fahrenheit the advantage that “decades” of temperatures are more useful as in saying the weather is in the 40s or the 70s, for instance. Because the Celsius degree is larger, the range of temperatures within any decade is wider and saying the temperature is in the 10s may not be as useful as it is a wider range of temperatures, compared to Fahrenheit. To many people, making the shift only partially may immediately seem very silly—and yet the people arguing for this are even more ardent than those that wish to shift entirely, perhaps precisely because of this immediate strangeness. Also, if someone is being an SI purist, supporting a full shift to SI units, one could argue they should be advocating a switch to Kelvin as the unit of thermodynamic temperature, even though Celsius has the status of an SI derived unit . Fahrenheit versus Celsius has been the topic of 1643: Degrees and 1923: Felsius . People who threw away their socks and bought all one kind The reason to do such a thing would be that any two socks in your drawer will match, saving time since they don't need to be matched or rolled/folded. It also reduces the likelihood of ending up with an unmatched sock—or a whole stack of them—in your drawer. This is a problem that scientists have researched . To ordinary people, it immediately seems quite aesthetically boring to always wear the same color of socks or other clothing. But it will be easier to find matching socks, so time is saved and there will be reduction in cost as no unmatched socks will have to be discarded. For those reasons, people that do this will recommend it quite ardently to all their friends, and, at least according to the comic, even more so than the pro-metric advocates. Randall previously referenced this idea in the xkcd survey (see 1572: xkcd Survey ) from September 2015. It included this question: People who open bananas from the other end The most evangelic people Randall includes are the people who open bananas from the "other" end. Some people prefer to open bananas from the calyx end instead of the stem end. This thought is continued in the title text. Title text The title text describes a fictional argument that apparently somehow tore apart Europe between the two factions Other primates open them from the small end and But the little bit of banana at the small end is gross . It continues the most evangelic point in the chart about how bananas are supposed to be opened from the “right” end. It seems absurd that this could have actually happened, over such a trivial issue. However, major schisms in religion, such as that between Catholicism and Protestantism (which did, in fact, split Europe) may seem similarly trivial to the non-religious. The supposed argument stems [ pun intended ] from a disagreement between those that find it easier to open a banana from the bottom and those that find the small bit at the base of a banana unappetizing. Though primates do not eat bananas in the wild , in captivity, some have been observed to open bananas from the bottom end away from the stem, as one of the two factions refers to. Less force is required to open a banana at the bottom than at the stem, causing less bruising of the fruit and generally making it easier to open. However, if not done carefully, this can result in the fruit getting squished and making a mess on the person’s fingers. Opening bananas from the stem end appears to be the predominant habit of most banana-eating humans (in Randall’s sample). One explanation is that using the stem as a lever makes for greater ease of opening and thus less damage in practice. (Bananas grow with the stem at the bottom ). The entire "correct banana end" discussion could be a reference to the wars between the Blefuscudians, who opened their eggs at the big end, and the Lilliputians, who broke their eggs at the small end, as told in Jonathan Swift’s epic novel Gulliver’s Travels . This in turn is the origin of the terms "Little Endian" and "Big Endian" which were much debated in circa 1980's computer architectures - which may also have been on Randall's mind. Randall’s thoughts on the problems with opening bananas could also explain why this fruit, which many find very easy to peel and consume, is listed in the middle of the easy/difficult scale in the 388: Fuck Grapefruit chart. [A chart is shown with a line drawn from left to right with five markers on it. Each marker has a line going to it from a labeled below the main line. Above this there is a title and right below that a label above an arrow pointing to the right.] People by intensity of evangelism More intense Religious proselytizers People who want the US to switch to metric People who want the US to switch to metric but keep Fahrenheit People who threw away their socks and bought all one kind People who open bananas from the other end

Clutter

Clutter

https://www.xkcd.com/1983

https://www.explainxkcd.com/wiki/index.php/1983:_Clutter

[There is a panel containing a line graph. The x- and y-axes are labeled "time" and "amount of stuff in my house" respectively.] [The y-value generally increases straight-line as x increases. There are a few labeled exceptions where the y-value decreases slightly but instantly increases again. From left to right:] "I need to clean up." "I've really let junk build up. Feels good to clear it out." "I hate moving, but at least it's a chance to finally get rid of all this excess stuff." "Ah, spring cleaning!" [Caption below the panel:] I'm starting to worry about my strategy for dealing with clutter.

As the graph shows, the amount of junk sitting around Randall 's house is on an ever-increasing trend. Thus, it will continue to pile up and cause problems. Randall cleans up sometimes, thinking that he is returning to the same baseline amount of stuff each time, but it is not actually effective enough to keep up with the cluttering trend, and hence his worry. The four places on the graph where the amount of stuff decreases reference common times when people clean up and get rid of junk or excess stuff. This includes: Although not mentioned in the quotes, it is also common in the United States to clean up and donate items (for instance to Goodwill) on December 31st, right before the New Year, to gain the charitable donation benefit on their taxes for that year. The title text refers to the book The Life-Changing Magic of Tidying Up: The Japanese Art of Decluttering and Organizing by Marie Kondo . The main concept of the book is that one should gather all belongings and only retain items that "spark joy". Ironically, the thought of reading the book didn't spark joy for Randall so he decided to donate it. Thus, one of the few things that he did get rid of was something that if he had kept and put into practice could have helped him actually reduce his clutter. [There is a panel containing a line graph. The x- and y-axes are labeled "time" and "amount of stuff in my house" respectively.] [The y-value generally increases straight-line as x increases. There are a few labeled exceptions where the y-value decreases slightly but instantly increases again. From left to right:] "I need to clean up." "I've really let junk build up. Feels good to clear it out." "I hate moving, but at least it's a chance to finally get rid of all this excess stuff." "Ah, spring cleaning!" [Caption below the panel:] I'm starting to worry about my strategy for dealing with clutter.

Misinterpretation

Misinterpretation

https://www.xkcd.com/1984

https://www.explainxkcd.com/wiki/index.php/1984:_Misinterpretation

[Cueball is sitting in an office chair at a desk in front of a laptop with his hands raised above the keyboard. An off-panel person replies to his remarks.] Cueball: Ugh, people are mad at me again because they don't read carefully. Cueball: I'm being perfectly clear. It's not my fault if everyone misinterprets what I say. Off-panel person: Wow, sounds like you're great at communicating, an activity that famously involves just one person.

Cueball is complaining that people are mad at him again because of a misinterpretation of his statements. This is referenced by the comic's title. He complains that since (he believes) he is being perfectly clear, it cannot be his fault that everyone misinterprets him. The off-screen voice sarcastically agrees that communication is an activity that only involves one person; in fact, of course, it famously involves at least two . Cueball speaks as though his communications are complete and perfect once he has finished making them. The reality is that communication can't be considered complete until the message has also been received and understood. Cueball is failing to take into account the need for partnership between sender and receiver, and doesn't realise that the problem may well be in the way he carries out his side of the transaction rather than in the way everybody else is carrying out theirs. In the title text, Cueball then answers that he cannot possibly account for the many possible interpretations which the message, potentially reaching the whole world, could acquire. This is an example of the Nirvana fallacy . Cueball's idealized solution is to consider how every person on Earth would interpret the message, so Cueball rejects doing anything less as insufficient; however, actually figuring out how every person on Earth would interpret the message is unfeasible, so Cueball doesn't do that either. The reply comes once again sarcastically, deriding his point and saying that a middle ground between taking up such an effort and entirely avoiding it must be reached. This avoidance is phrased using a simile as “covering your eyes and ears and yelling logically correct statements into the void”, implying that no one would understand the logical sentences (thus the void), and would instead read them more naturally – and also that ignoring the appalled reaction of listeners to their own interpretation of the sentences is similar to covering your eyes and ears. This action makes communication more difficult through the popular [ citation needed ] means of speech, text and sign language. If the hands are occupied with covering either part, then Braille communication is also impossible. Therefore, the action of “covering your eyes and ears” is a metaphor for deliberately making it more difficult to communicate with oneself. The simile might also mean that Cueball subconsciously rejects criticism as it would hurt his ego. It is clear that Cueball is acting as a straw man to further Randall's point, and the off-panel character is portrayed as the (sarcastic) voice of reason. Randall returns to a recurring theme in his comics, regarding, in contexts of communication, the responsibility of the speaker for how they are interpreted. Having gradually gotten less subtle, this theme is now laid bare, there being no joke other than the sarcasm. What follows is a chronological history of this theme. This theme is part of the larger category of comics about social interactions . [Cueball is sitting in an office chair at a desk in front of a laptop with his hands raised above the keyboard. An off-panel person replies to his remarks.] Cueball: Ugh, people are mad at me again because they don't read carefully. Cueball: I'm being perfectly clear. It's not my fault if everyone misinterprets what I say. Off-panel person: Wow, sounds like you're great at communicating, an activity that famously involves just one person.

Meteorologist

Meteorologist

https://www.xkcd.com/1985

https://www.explainxkcd.com/wiki/index.php/1985:_Meteorologist

[Cueball is presenting a weather forecast while seated with his folded hands resting on a table. A graphic to the left of Cueball shows the weather for five consecutive hours from 12pm to 4pm, each with a rainy cloud icon and the same percentage of 20% written below the icon. The TV channel's logo is shown on the bottom left, with the 4 in a white font inside a black circle.] Cueball: Our forecast says there's a 20% chance of rain for each of the next five hours. Cueball: How likely is it to rain this afternoon? It's a simple question, but I don't know the answer. Is each hour independent? Correlated? Or is rain guaranteed and we're just unsure of the timing? 12pm  1pm  2pm  3pm  4pm 20%  20%  20%  20%  20% News 4 Weather [Cueball still sits at the table, but the weather graphic is gone and he looks to the right.] Cueball: It says "scattered showers." Is this the chance of rain somewhere in your area? How big is your area? What if you have two locations you're worried about? Cueball: I've asked management, but they've stopped answering my emails, so—Hang on, the security guy is coming over. [A black screen is shown with white text and two short white lines between each of the three segments of text. The TV logo is shown below the last text, with the white 4 inside a gray circle with a white border.] Technical Difficulties — We apologize for hiring a meteorologist with a pure math background. — We'll be back on the air shortly. News 4 [Blondie now sits at the desk, in the same position as Cueball, but without the graphic. She looks to the right towards a person who speaks to her from outside the panel. This voice is indicated with two square speech bubbles, connected with a double line and with a small arrow pointing to the right off-panel from the top bubble.] Blondie: Sorry about that. Hi, I'm your new meteorologist. Person off-panel: And you're not a mathematician, right? Blondie: No. I do have a linguistics degree. Person off-panel: That's fine. [Blondie continues in the same position but now looks into the camera at the viewers. The off-panel person only speaks one word, which again is inside a square speech bubble with a small arrow pointing to the right off-panel.] Blondie: It might rain this afternoon. Blondie: But what is "it" here? Is it a true dummy pronoun, as in the phrase "It's too bad?" Or is the weather an entity? Blondie: Also, what if I say, "It's hot out, and getting bigger?" Person off-panel: Security!

Although we’re constantly exposed to them, many (most?) people don’t understand the details of how to properly interpret weather forecasts. But even beyond the normal questions, there can be much more complex issues hiding beyond those (though most people will not care for those). This comic takes this to the ridiculous extreme of the weather reporters coming from some other profession where you look into those questions. It shows questions asked by three different people with different backgrounds: mathematics , linguistics , and (in the title text) software development . While some of those questions have actual answers (which you'd expect someone working in that job to know, such as the definition of "scattered showers" and how it's determined, what a "chance of rain" means, and so on), each professional finally ends up with questions that are almost disturbing in how they cannot be answered. (So management ends up calling security to remove those announcers.) It should be pointed out that hiring someone without any meteorological training to read the weather does not make them an actual meteorologist, no more than say hiring a bricklayer as a doctor would actually make them a real doctor. The first meteorologist, Cueball , has a background in pure math. His forecast states that each of the next five hours has a 20% chance of rain. As a mathematician he sees how limited that information is. There is no information about whether or how those probabilities are correlated . This becomes obvious if you ask the question "How likely is it to rain this afternoon" (a question even some non-mathematicians might be interested in). Cueball states that he does not know (as no one only getting the information about 20% rain in each hour can know). And then lists some scenarios that all fit the the description, but have totally different results for "How likely is it to rain this afternoon?" The first thing a mathematician would ask (and Cueball does here) is asking if those 5 events are independent . Events are independent if the outcome of one of them is unrelated to the outcome out of the others, i.e. knowing whether it rained at 3 pm has no effect on whether it rains at 4 pm, in which case the probability of any rain over the 5 hours is 1 − (1 − 0.2) 5 = 67.2%. (Rain is very seldom independent, as usually having rain in one hour increases the chance to rain in another hour, as systems of rainy weather usually persist for many hours). Another common extreme in probability theory is a set of mutually exclusive events. In this example that would be the scenario that the chance of rain is 5 × 20% = 100%, but it will only rain in exactly one hour and not rain at all for the other four. (Also possible but quite unlikely). This is what the mathematician was referring to by, "Is rain guaranteed and we're just unsure of the timing?" In the second panel he continues to discuss what scattered showers means. Like most of the other weather terms in this comic, the term "scattered showers" is one whose technical definition is largely unknown but appears simple enough that most people would assume they understand what it means. "Scattered" refers to when the rain covers roughly 30–50% of the area at a given moment. To somebody who doesn't know this, like the first meteorologist, there's still the very valid question of how likely it is to rain in a specific spot (is it 30–50% of the total probability, or is it more than that because showers move and sweep out a larger area?), and how this is affected by the previous chance of rain. Not to mention, the percentage that defines "scattered showers" implicitly assumes a surface area that is accounted into the percent. Cueball rightly asks clarification on how large the location used to determine "scattered showers" is. While the all but the last question of the first part of the second panel can be answered by looking up their definitions, the last one is "What if you have two locations you are worried about?" This is an extremely complex question. Because there is no chance at all to answer this question from the answers of the previous questions or even from most other data a forecast might usually produce. To answer this you'd need the raw data from the ensemble forecast in order to specifically look at the correlation between weather at those two locations. Simply looking at the averaged result won't help. Finally in that panel Cueball begins to explain that he has asked the management about these things, but that they have stopped replying to his e-mails. At this point he spots the security guy coming over, and the screen goes black in to a technical difficulty screen that excuses this behavior to the viewers. It is implied that the security guy came over to force Cueball to leave the set, because he has been fired for confusing the viewers. Questioning these things on air is likely confusing to the viewers, although they are all valid questions. But this may lose viewers and the news network is afraid of this. The technical difficulty panel further cements this, apologizing for hiring a person with a pure math background. Often seen as one that do not understand how to talk to regular people. When they get back on air gain a new meteorologist, Blondie , steps in. The management enquires (on air) to make sure she is not also a mathematician. She states no, but tells that she has a linguistics degree, which the management thinks is fine, and thus believes they have prevented the problem with Cueball. However, this proves to be in vain, as Blondie goes into a tangent once more but from a linguistics standpoint, rather than a mathematical one, detailing the true meaning of the word "it" as referring to the weather. After one panel of this the management calls for security again. While, at the most basic level, human speech is broken into subject, object, and verb; for some reason we are capable of producing and comprehending speech without both objects or verbs, but in English there is a certain "resistance" to speech without a subject. Thus if you are in the passenger seat of a car going down the highway and happened to see some deer in the trees nearby, you could simply say "Deer.", rather than "there is a deer over there", deer being the subject of the sentence. However, if you noticed that it had begun to rain, you could not simply say "Raining." on it's own. Feel how that sentence just seems weird? Hence we have developed the tendency to use the filler word "it" despite the fact that when we say "It's raining." the "it" is not a reference to the clouds producing the rain, but the general state of the rainfall around us. (McWhorter, John. Understanding Linguistics: The Science of Language. https://www.thegreatcourses.com/courses/understanding-linguistics-the-science-of-language.html ) The first question is again quite harmless, and both possible answers ("it" being a dummy pronoun or referring to the weather) are valid answers, but the second question is much more disturbing. In "It's hot out, and getting bigger" the first part of the sentence might be a dummy pronoun or it might reference the weather. But the second part breaks it: With a dummy pronoun "getting bigger" would be the impersonal action, which is not what is meant. It is referencing something (the hotness, that is getting bigger). But if the it references this entity in the second part, by grammatical rules it would also have to reference that in the first part. But "The hotness is hot out" makes no sense at all. (An alternative explanation is that the sentence is referring to the fact that if a dark (so as to absorb light energy from sunlight and convert it to thermal energy) object is placed outside in sunlight, it will heat up and undergo thermal expansion.) This is again a common occurrence with informal speech: From a grammatical point of view, it is pure non-sense. But it still has meaning people understand. So if you want a proper descriptive grammar, it needs to cope with those cases. But then most such informal sentences would be special cases. (Case of point: What is the grammatical function of the "out" in that sentence?) In the title text, the news station has made the same error again, this time by hiring a software developer as the third meteorologist. This last person is stating concerns about the feasibility of the time system used to correlate to the weather patterns. Because it appears simple, many people would simply assume they understand what is being said when a meteorologist talks about "12pm" or "1pm". This is a common mistake because noon is neither post meridiem (pm) nor ante meridiem , and should be stated as "noon" or "12 noon" instead of "12 pm.". However, because software developers frequently have to deal with things such as specifying exactly what time-label means what, the new meteorologist begins to wonder what time period is actually meant on a per-hour forecast. On such an hour forecast does 12pm refer to the hour from 12 to 1pm, from 11:30 to 12:30 or is it actually only to the weather precisely at 12:00 that is referred to? The software developer also worries about an off-by-one error , which is a common error in software development occurring when boundary conditions include one element too few or too many: when counting by 24 once every set period (for example), it is common to forget whether the count should stop at 23 or at 24, especially if the number 0 (midnight) is included. In the 24-hour forecast, that means there's 25 hours represented every day, and the software developer worries that these 25 hours might add up and, every progressive day, the forecast is one more hour off. (If the news station's meteorology department had been around for a while, worrying about this would be absurd because if the new station tried to predict the weather one hour further into the future each day, it would eventually ask for the weather further into the future than the forecast models could supply, resulting in an error that someone would definitely notice (and it would likely be the case that long before that happened, someone would perceive the weather forecasts as being inaccurate or early). However, based on how quickly the linguist was fired, this was likely either the mathematician's first day or second day on the job, so if we assume that the mathematician was the first meteorologist (or that all previous meteorologists were fired quickly enough that the mathematician started within a few days of when the meteorology department started), there wouldn't have been enough time for the effects of an off-by-one error to stack up enough to be noticed, so the software developer's concern about an off-by-one error would not have been ruled out yet.) In theory these are valid concerns and notably less inane than his predecessors, but they are all things he should have asked before he went on the air. Management would certainly answer the mathematician's questions! The questions themselves have been asked of meteorologists before. The National Weather Service (NWS), a unit of the United States National Oceanic and Atmospheric Administration (NOAA), has published relevant answers for probability of precipitation , as well as timing and the meanings of particular forecast words . The naming is also addressed here . Regarding probability of precipitation, NOAA forecasts give the probability that it will rain at all at any given point in an area. To rephrase it, it is the probability of rain occurring at all within a forecast area multiplied by the percentage of area affected by the rain. The "forecast area" is a clearly defined area of land and can be seen in the map of any official NWS forecast. Here is an example . Regarding the timing of the forecast, an hourly forecast gives the probability for each particular hour, stretching from the time listed to right before the next hour listed. So, the forecast for noon describes the time period from noon to 1pm. The forecasts for individual hours can be correlated; for this reason, the NOAA generates forecasts that stretch over longer time periods, giving a useful estimate for that time range. Thus, the chance of rain for "Today" specifically means: what is the chance of it raining at any given location during any time between 6am and 6pm? Regarding phrases like "scattered showers", this specifically means a 25-54% probability of precipitation from convective cloud sources. Other phrases, and when they are used, are detailed in the chart at the end of this PDF . So, to conclude: [Cueball is presenting a weather forecast while seated with his folded hands resting on a table. A graphic to the left of Cueball shows the weather for five consecutive hours from 12pm to 4pm, each with a rainy cloud icon and the same percentage of 20% written below the icon. The TV channel's logo is shown on the bottom left, with the 4 in a white font inside a black circle.] Cueball: Our forecast says there's a 20% chance of rain for each of the next five hours. Cueball: How likely is it to rain this afternoon? It's a simple question, but I don't know the answer. Is each hour independent? Correlated? Or is rain guaranteed and we're just unsure of the timing? 12pm  1pm  2pm  3pm  4pm 20%  20%  20%  20%  20% News 4 Weather [Cueball still sits at the table, but the weather graphic is gone and he looks to the right.] Cueball: It says "scattered showers." Is this the chance of rain somewhere in your area? How big is your area? What if you have two locations you're worried about? Cueball: I've asked management, but they've stopped answering my emails, so—Hang on, the security guy is coming over. [A black screen is shown with white text and two short white lines between each of the three segments of text. The TV logo is shown below the last text, with the white 4 inside a gray circle with a white border.] Technical Difficulties — We apologize for hiring a meteorologist with a pure math background. — We'll be back on the air shortly. News 4 [Blondie now sits at the desk, in the same position as Cueball, but without the graphic. She looks to the right towards a person who speaks to her from outside the panel. This voice is indicated with two square speech bubbles, connected with a double line and with a small arrow pointing to the right off-panel from the top bubble.] Blondie: Sorry about that. Hi, I'm your new meteorologist. Person off-panel: And you're not a mathematician, right? Blondie: No. I do have a linguistics degree. Person off-panel: That's fine. [Blondie continues in the same position but now looks into the camera at the viewers. The off-panel person only speaks one word, which again is inside a square speech bubble with a small arrow pointing to the right off-panel.] Blondie: It might rain this afternoon. Blondie: But what is "it" here? Is it a true dummy pronoun, as in the phrase "It's too bad?" Or is the weather an entity? Blondie: Also, what if I say, "It's hot out, and getting bigger?" Person off-panel: Security!

River Border

River Border

https://www.xkcd.com/1986

https://www.explainxkcd.com/wiki/index.php/1986:_River_Border

[Ponytail and Megan are standing on a grassy riverbank, with the nearby part of the river shown above their heads. They are looking towards the river and Ponytail is gesturing at the river with her hand.] Ponytail: This is a cool spot. Ponytail: The Missouri-Nebraska state line follows this river. If the river's path changes gradually, the border moves with it. [A map is shown beneath the text spoken by Ponytail (off-panel). The map includes a bendy river shown in gray which is snaking its way from the left part of the panel down to the bottom. A dotted line indicates the old path of the river. It follows the gray river most of the way, but towards the bottom, this line moves away from the current river extending to north-east, including a large chunk of land that the river used to encompass previously. Two arrows point to the gray section of the river with the dotted line, and another arrow points to the section of the dotted line not following the gray section. Both are labeled. On each side of the dotted arc, where it is farthest from the gray part of the river the state names are labeled, so the text follows the direction of the river (almost north to south here).] Ponytail (narrating): But when it abruptly changes course, the border stays behind. Ponytail (narrating): This is a spot where that happened. We're on the Missouri side, but we're in Nebraska. River Old riverbed Nebraska Missouri [In a frame-less panel (with no background) Ponytail has turned to look at Megan who is holding a hand to her chin.] Megan: Wow. Megan: So... Megan: We can commit all the crimes we want here and the cops can't do a thing! [Megan runs away from Ponytail while she is holding her arm up in the air with a finger extended up.] Ponytail: What? No. Why would you even think that? Megan: I'm going to cut a pizza into a spiral! Ponytail: That's not even illegal! Megan: Crimes!

Ponytail explains to Megan that the Missouri-Nebraska state border is based on the Missouri River they are watching. And because the path of rivers mostly only changes slowly, these borders are typically adopted to that changes. But then she explains that the river once had changed abruptly by a meander cutoff and the border didn't move with it. That means that they are on a part of the Missouri side of the river that in fact belongs to Nebraska. It then occurred to Megan that she could break the law in this area because she is under the mistaken impression that she is in Nebraska but the police can't reach her over the river and Missourian cops actually don't have jurisdiction. In fact, there are no bridges linking it to Nebraska so police would have to go through Missouri in order to get to that part of Nebraska. It should be noted that there are real-world examples of strange border interactions that either create legal loopholes or make law enforcement difficult. A famous example, in the US, is a section of Yellowstone National Park that crosses over the Idaho border. An article in the Georgetown Law Review noted that, since the Park is a federal district, and juries must be selected from people living in the same state and federal district as the crime, the only qualified jurors would have to live in the Idaho section of the park, but that section has no permanent residents. In theory, then, any crimes committed on this patch of land could not be prosecuted. How this would work out in real life remains questionable, as there are no records of anyone being arrested for a crime in that region, but the law seems to have inadvertently created a zone in which laws cannot be enforced. Similarly, Bir Tawil , a region along the border between Egypt and Sudan, is claimed by neither country as a result of the Halaib Triangle border dispute, and thus crimes committed in the area would be unlikely to be prosecuted. Megan seems to mistakenly think something similar is in effect any time a state's border briefly crosses a river. The final panel shows Megan saying she's going to cut a pizza into a spiral, which while unconventional is by no means illegal, and she runs off to commit more things she calls crimes, likely similar acts to cutting a pizza in an uncommon way. In the title text, Randall claims/hypothesizes the disputed region is probably considered like the high seas , suggesting the pizza case would then fall under maritime law . "Pieracy" is a portmanteau of pie (another name for a pizza) and "piracy"; and pizzas are frequently made with marinara sauce, so "Maritime" law is rendered "Marinaritime". This is most likely a reference to The Martian , in which it was noted that Mars is technically international waters as well. The region mentioned in the comic can be seen here at Google maps and is known as McKissick Island . In 1904, the U.S. Supreme Court confirmed in Missouri v. Nebraska that a sudden change of a river's course does not change any border. See: Missouri v. Nebraska, 196 U.S. 23 (1904) . This strip is alluding to the concepts of 'accretion' and 'avulsion' in boundary law. Accretion is the gradual change of the location of a river or stream by erosion or addition of sediment through natural river processes. According to common law in the United States and elsewhere, if a river or stream location changes gradually, then the boundary line moves with the stream. In cases of pure accretion, it is possible for a parcel of land to be entirely eroded away on one side of a river, and have material be added to the opposite side of the river. In such cases, one property owner could lose all their land. An avulsion is a sudden change in the location of a river or stream, often due to flooding. In times of flood, a river can cut a new channel through surrounding land, which can create islands and oxbow lakes. According to common law, an avulsive change will not change the boundary of the land, as it is likely that the property is unchanged except for the new channel. In the real world, however, river systems undergo both accretion and avulsion multiple times over a period of time. This makes the determination of property lines along riverine boundaries one of the most complicated aspects of boundary surveying. An examination of a river boundary will require in-depth research of the local history of the river, including reviewing deeds, government survey plats, private survey maps, aerial photos taken over time, local landowners recollections, and local lore. In situations where there is disagreement over whether an avulsive or accretive change happened, landowners may have to go to court for a suit to quiet title. Further in-depth reading may be found in the US Bureau of Land Management's 2009 Manual of Surveying Instructions, Chapter 8, specifically pages 197-205. (See: PDF (37.7 MByte) .) Often, borders defined by a river actually change. There are three methods to define a border: The Mexican-US-Border that follows the Rio Grande is one of the most prominent examples of an international border that needs meticulous regulation. Thus, the International Boundary and Water Commission was created. This commission was involved when the two nations rectified the course of the river, ceding equal amounts of land to each other. The Canada-US-Border is overseen by a similar commission. There is also a strange section on the border to Canada, which Randall mentions in this comic: 1902: State Borders . The border between Delaware and New Jersey veers from the median and talweg methods such that Delaware's border includes all the way to the New Jersey shore where the Delaware River is within what is known as the Twelve-Mile Circle . One of the causes of the Iran-Iraq War was the dispute on shipping rights on the Shatt-el Arab river , and because the border was defined as the low water mark at the eastern side of that river, Iranian shipping was severely restricted. So the Shah of Persia announced to ignore the 1937 treaty on shipping rights, saying that most riverine borders all around the world are defined by the talweg. Between Switzerland and Italy, the border is, at most locations, defined by the actual drainage divide . Because the Theodul Glacier between Zermatt (Switzerland) and Breuil-Cervinia (Italy) is slowly melting, the drainage divide moves southwards, thus slowly enlarging the Swiss territory. Most other national borders in Europe are defined today as fiat borders instead of following natural landmarks like rivers. If a river changes course now, the depicted situation would occur; however, most larger rivers have been rectified more than a century ago and thus don't change course often. [Ponytail and Megan are standing on a grassy riverbank, with the nearby part of the river shown above their heads. They are looking towards the river and Ponytail is gesturing at the river with her hand.] Ponytail: This is a cool spot. Ponytail: The Missouri-Nebraska state line follows this river. If the river's path changes gradually, the border moves with it. [A map is shown beneath the text spoken by Ponytail (off-panel). The map includes a bendy river shown in gray which is snaking its way from the left part of the panel down to the bottom. A dotted line indicates the old path of the river. It follows the gray river most of the way, but towards the bottom, this line moves away from the current river extending to north-east, including a large chunk of land that the river used to encompass previously. Two arrows point to the gray section of the river with the dotted line, and another arrow points to the section of the dotted line not following the gray section. Both are labeled. On each side of the dotted arc, where it is farthest from the gray part of the river the state names are labeled, so the text follows the direction of the river (almost north to south here).] Ponytail (narrating): But when it abruptly changes course, the border stays behind. Ponytail (narrating): This is a spot where that happened. We're on the Missouri side, but we're in Nebraska. River Old riverbed Nebraska Missouri [In a frame-less panel (with no background) Ponytail has turned to look at Megan who is holding a hand to her chin.] Megan: Wow. Megan: So... Megan: We can commit all the crimes we want here and the cops can't do a thing! [Megan runs away from Ponytail while she is holding her arm up in the air with a finger extended up.] Ponytail: What? No. Why would you even think that? Megan: I'm going to cut a pizza into a spiral! Ponytail: That's not even illegal! Megan: Crimes!

Python Environment

Python Environment

https://www.xkcd.com/1987

https://www.explainxkcd.com/wiki/index.php/1987:_Python_Environment

[A single frame depicting a flowchart is shown. Many chaotic arrows are arranged between the items which are:] $PYTHONPATH EASY_INSTALL ANACONDA PYTHON HOMEBREW PYTHON (3.6) ANOTHER PIP?? HOMEBREW PYTHON (2.7) PYTHON.ORG BINARY (2.6) PIP EASY_INSTALL $PATH (MISC FOLDERS OWNED BY ROOT) ???? [The endpoints are:] /usr/local/Cellar /usr/local/opt /(A BUNCH OF PATHS WITH "FRAMEWORKS" IN THEM SOMEWHERE)/ ~/python/ ~/newenv/ /usr/local/lib/python3.6 /usr/local/lib/python2.7 [Caption below the panel:] My Python environment has become so degraded that my laptop has been declared a superfund site.

A development environment is the collection of tools used to create a computer program. It generally includes an interpreter , a package manager , and various libraries that the project needs. Computer programs often depend on a specific version of these tools, such as a program that only runs on Python 2.7. A badly configured build environment can lead to mysterious errors as the program looks for libraries or features that aren't there, making it hard to develop stable and portable software. Python is a computer programming language which has been around for quite a while, especially on Linux platforms. Randall has shown his fascination with Python before . He has likely used it on his computer for quite a few years, from the early years when it wasn't so easy to install, through newer versions where there is a more defined way to install it. Because standards change over time (in particular, although the newest version of Python is Python 3.x, many people prefer Python 2.x, and it's still widely used for backward-compatibility), and he didn't completely uninstall old versions before installing new versions (likely to not break what was already working), he's ended up with a mess where different pieces and versions of Python and its related components litter his hard drive 's directory structure . Superfund is a US federal government program created for cleaning up contaminated land. The comic is saying that his computer's Python environment is so messed up that it's comparable to a real-world environmental disaster. The title text may refer to the philosophical debate surrounding the construction of warning features around the WIPP site in New Mexico, and other nuclear waste disposal sites. In particular, it may refer to this article . These would have to last and be understandable for tens of thousands of years, longer than any known human-made structure or language to date. It also refers to the use of "sudo", a Posix command utility that allows a user to operate with heightened permissions. Using "sudo" to install a Python package may make the package available to the entire system, or, based on the settings of Virtualenv/Anaconda, it may end up installing the package in a user's home directory. This would make it so that the user could not update, edit, or remove the packages. $PATH $PATH refers to the PATH environment variable, which determines where to search for executable files. In this case, it indicates that the pip, Homebrew Python (2.7), and macOS's pre-installed Python are accessible on path, with ~/newenv/ and a mysterious ???? as part of PATH. pip pip is the Python package management system , and is used to install and manage python packages. As it is written in Python, it requires Python to run. It leads to easy_install, Homebrew Python (2.7), "(misc folders owned by root)", and ????. Homebrew Python (2.7) Homebrew is a third-party macOS package manager. Homebrew Python (2.7) is the Python 2 version installed through Homebrew. This leads to Python.org binary (2.6) and /usr/local/Cellar. OS Python Apple bundles an (out of date) version of Python with macOS. This only leads to ????. ???? With so many versions of Python installed and used in the system, it becomes very hard to track which Python program uses which version and environment. The system becomes unpredictable and its workings and faults mysterious. All parts of the graph that lead to this point, lead to confusion. easy_install easy_install, much like pip, is a cpan-like tool to download and install Python packages. As of the creation of the comic, many people discourage its use. (e.g., this question on stack exchange. ) Anaconda Python Anaconda is a Python distribution for data science and machine learning-related applications. Homebrew Python (3.6) As of the creation of the comic, Python 3.6 is the current stable version of Python. It can be installed together with Python 2.7 on the same computer. Care must be taken to use an appropriate version for every Python program, however. Homebrew is a "macos" package management utility. Presumably, Randal installed Python 3.6 with Homebrew (as opposed to downloading and compiling the language himself). Python.org binary (2.6) Python.org is the home site of the Python language and provides its reference implementation. Among other stuff, there are downloadable installers that create ready-to-use Python environments for you (on Windows and macOS only). It makes little sense, however, to use it on a computer where Homebrew, Anaconda, and a locally compiled version are already present, since the Python.org version is the baseline one, doesn't give you any benefits, and can't be optimized for your needs. Having an obsolete 2.6 version, when the typically used 2.7 is already on the computer, also doesn't help. Some justified uses do exist (tests, programs that depend on this particular version), but in the end, an extra version of Python just adds to the overall confusion. (Misc folders owned by root) This suggests that over years Randall dropped various versions of Python environments everywhere around his computer, probably by hand without proper installers, and used root privileges to do so. The exact locations either are highly nonstandard, so it makes no sense to show them to us, or have simply been forgotten. Now it's hard to even tell where exactly those Pythons lay, what in the system depends on them, and if it's safe to remove them or not (because if installed by the root, they can integrate into unexpected places in the system; having them can break something, and removing them can break something). /usr/local/Cellar The default (normal) location of the Homebrew Cellar, the directory where Homebrew actually stores the files of the installed packages. It's a storage-only location, the files, including Python, will be symlinked from other, more convenient places in the files tree, and should not be used through /usr/local/Cellar path directly. It seems that Randall broke this safety rule in the past, so some stuff of his accesses Python directly in the Cellar. Such setup can break if Homebrew performs automatic maintenance in the Cellar (like removing unneeded versions of the packages). The name cellar is likely a reference to the practice of storing wines and other alcohol in cellars, intended as a pun of homebrew. /usr/local/opt A folder that is usually created by Homebrew. /(A bunch of paths with "Frameworks" in them somewhere)/ Python on macOS is often distributed as a framework and placed in a "Frameworks" folder. For example, the system-included Python distribution in macOS resides in /System/Library/Frameworks, and many package managers will also install the framework in a folder with this name. $PYTHONPATH The environment variable PYTHONPATH specifies the search path for Python modules to the Python interpreter. Having it refer to locations controlled by 3 different package managers, each of which is managing software for different versions of Python, as shown, is likely to lead to incompatible software being loaded together. Another pip?? Pip is a Recursive acronym for "Pip Installs Packages." There should only be one installation of pip (or other package management system) managing any given working environment. Often, additional "pip" executables are installed based on the Anaconda settings for different virtual envs. This often leads to internal contradictions in the software. Randall is confused as to how this other one relates to the rest of the development environments. ~/python/ Might be another virtualenv, or, given the absurdity of the rest of the comic, even a manually compiled python installation (many online guides instruct users to extract sources into the home (~) directory). ~/newenv/ Probably a virtualenv. Virtualenvs are mechanisms for having Python environments that don't conflict with the system Python. They include the Python interpreter, independent library paths, and usually a copy of pip. The user typically installs packages using the virtualenv's pip such that they can only be accessed by the virtualenv's Python instances, while more common packages are still referenced via the system Python paths. /usr/local/lib/python3.6 The default place under a Unix-like OS for the Python 3.6 standard libraries for a locally compiled Python 3.6 interpreter. /usr/local/lib/python2.7 The default place under a Unix-like OS for the Python 2.7 standard libraries for a locally compiled Python 2.7 interpreter. [A single frame depicting a flowchart is shown. Many chaotic arrows are arranged between the items which are:] $PYTHONPATH EASY_INSTALL ANACONDA PYTHON HOMEBREW PYTHON (3.6) ANOTHER PIP?? HOMEBREW PYTHON (2.7) PYTHON.ORG BINARY (2.6) PIP EASY_INSTALL $PATH (MISC FOLDERS OWNED BY ROOT) ???? [The endpoints are:] /usr/local/Cellar /usr/local/opt /(A BUNCH OF PATHS WITH "FRAMEWORKS" IN THEM SOMEWHERE)/ ~/python/ ~/newenv/ /usr/local/lib/python3.6 /usr/local/lib/python2.7 [Caption below the panel:] My Python environment has become so degraded that my laptop has been declared a superfund site.

Containers

Containers

https://www.xkcd.com/1988

https://www.explainxkcd.com/wiki/index.php/1988:_Containers

[White Hat is sitting at a laptop. Cueball is standing behind him.] White Hat: Man, Docker is being used for everything . White Hat: I don't know how I feel about it. Cueball: Story time! [Cueball is standing by himself.] Cueball: Once, long ago, I wanted to use an old tablet as a wall display. [A picture of Cueball's imagined tablet with two applications open side by side. The app on the left is "LiveCam". The app on the right is Google Calendar.] Cueball: I had an app and a calendar webpage that I wanted to show side by side, but the OS didn't have split-screen support. Cueball: So I decided to build my own app. [White Hat and Cueball as before, but White Hat has turned to face Cueball.] Cueball: I downloaded the SDK and the IDE, registered as a developer, and started reading the language's docs. [A picture of two smartphones glued together side by side, held on a backing board. The same two applications shown earlier are open on different phones.] Cueball: ...Then I realized it would be way easier to get two smaller phones on eBay and glue them together. Cueball: On that day, I achieved software enlightenment. [White Hat and Cueball still facing each other, with White Hat's arm resting on the back of the chair.] White Hat: But you never learned to write software. Cueball: No, I just learned how to glue together stuff that I don't understand. White Hat: I...OK, fair.

Docker is a computer program that performs operating-system-level virtualization also known as containerization. White Hat notices that many people are using Docker for "everything," implying that he does not understand what all the fuss is about. Cueball then explains the fundamental idea behind Docker with a simple story. He notes how difficult it can be to combine two programs and have them work together as one. This is something all programmers can relate to. His specific example is to get two separate programs to display side-by-side on a tablet. The main joke is that Cueball's solution is a surprising twist to solving the problem. Instead of writing a lot of complicated code to deal with the problem at hand, he sidesteps the problem by using two separate devices, literally gluing them together. Containerization software, like Docker, uses the same general idea but the "glue" and the "multiple computers" are done in software, instead of literally gluing two computers together. Cueball states that he achieved "software enlightenment" when he "solved" the problem by sidestepping it. White Hat's initial confusion comes from the fact that Cueball did not write any software, yet achieved "software enlightenment." A good programmer doesn't necessarily need to be able to write programs or even understand how they work, provided that they have the skills needed to combine existing programs to solve tasks. An alternate interpretation is that someone with little programming experience is able to create a working program simply by copy/pasting code snippets from a coding site such as Stack Overflow and "gluing" them together without really understanding how they work. The title text makes a joke about developers writing code for use in a containerized environment. The ideal is to only write " microservices " which are modules that do just one thing and do it well. The joke here is that even when a module does many different things, you can pretend it is a "microservice" by just ignoring all of its features but one (hopefully one that it does well). [White Hat is sitting at a laptop. Cueball is standing behind him.] White Hat: Man, Docker is being used for everything . White Hat: I don't know how I feel about it. Cueball: Story time! [Cueball is standing by himself.] Cueball: Once, long ago, I wanted to use an old tablet as a wall display. [A picture of Cueball's imagined tablet with two applications open side by side. The app on the left is "LiveCam". The app on the right is Google Calendar.] Cueball: I had an app and a calendar webpage that I wanted to show side by side, but the OS didn't have split-screen support. Cueball: So I decided to build my own app. [White Hat and Cueball as before, but White Hat has turned to face Cueball.] Cueball: I downloaded the SDK and the IDE, registered as a developer, and started reading the language's docs. [A picture of two smartphones glued together side by side, held on a backing board. The same two applications shown earlier are open on different phones.] Cueball: ...Then I realized it would be way easier to get two smaller phones on eBay and glue them together. Cueball: On that day, I achieved software enlightenment. [White Hat and Cueball still facing each other, with White Hat's arm resting on the back of the chair.] White Hat: But you never learned to write software. Cueball: No, I just learned how to glue together stuff that I don't understand. White Hat: I...OK, fair.

IMHO

IMHO

https://www.xkcd.com/1989

https://www.explainxkcd.com/wiki/index.php/1989:_IMHO

[Cueball, Megan, and Ponytail stand together, talking.] Cueball: I thought the "H" in "IMHO" was "humble," but Buzzfeed ran a poll and "honest" won. Megan: That can't be true. Their readers are messing with us. [Cueball and Megan look at Ponytail.] Ponytail: Are you sure? I always used it to mean "honest." Megan: ...What?! [Close up of Cueball holding a phone. A box with usage of "IMHO" and "TBH" from Google Trends shows "TBH" suddenly rising in 2011, with a second spike in 2014.] Cueball: It was definitely "humble" in the 1990s. Cueball: Maybe people who picked it up after the rise of "TBH" in 2011 interpreted it as "honest" and used it that way. [Cueball, Megan, and Ponytail as before.] Megan: I can't get over this. What other wrong opinions do you have? Megan: The "G" in "G-I-F"? Ponytail: Silent. [Close up of Ponytail, with Megan talking from offscreen.] Megan: The "S" in "SMDH"? Ponytail: "Swallowing." Megan: The "G" in "OMG"? Ponytail: "Giantess" or "genitals." [Cueball, Megan, and Ponytail as before.] Megan: The Dress? Ponytail: Black and white. Megan: Is the database language "sequel" or "ess cue ell"? Ponytail: I've always said "squill." Cueball: Okay, the big one: how many spaces after a period? Ponytail: None; I use tabs. Cueball: OMG. Megan: Yeah, mine too.

The conversation begins with a reference to the controversy between whether IMHO stands for "in my honest opinion" or "in my humble opinion". Some older Internet users, including Cueball, use the H to mean "humble", which Cueball references as being the norm in the 1990s. However, many younger Internet users, including, apparently, Ponytail, use it to mean "honest", which became the norm after another SMS abbreviation, TBH (to be honest) became popular c. 2011 [1] . However, the joke veers into absurdity with Ponytail sharing her unusual opinions on other Internet controversies, including: Before the 20th century, it was common typographical practice to use an em-space (or other similar wide-space) between sentences. In the 1930s, common practice was to use smaller inter-sentence spacing, and by the 1950s, inter-sentence spaces were the same size as inter-word spaces. Although modern style guides all insist on single-spacing between sentences, many people prefer to include two spaces, possibly out of habit from typewriter usage (which commonly used two spaces to mimic the 19th century typographic standards). (See also: 1285: Third Way .) Tabs vs. Spaces also refer to the programmers' debate on how to indent code correctly. In the last panel, Cueball exclaims "OMG" (meaning "Oh, my God") to which Megan replies "Yeah, mine too", taking the meaning as "Oh, my genitals" from the 5th panel. This leads to the title text "TMI" (too much information). The pun on periods (typographical and menstruation) might also explain the reaction. In the title text, another incorrect belief Ponytail has is believing TMI to be "tantalizing meat info," as opposed to too much information. (Remarkably, this makes sense in the context of Megan's comment about her genitals.) The comic also obliquely references the mistaken opinion that Website polling is an accurate measure of anything; selection bias (among many other problems) renders them almost useless for measuring the general population. Etymology of IMHO ESR's Jargon File (later known as The New Hacker's Dictionary) has an entry of "IMHO" . It's also seen in variant forms such as IMNSHO (In My Not-So-Humble Opinion) and IMAO (In My Arrogant Opinion). And it has been added into the Jargon File v2.1 in January 1990 , the first version under Eric S. Raymond. Maybe the acronym "IMHO" was invented by science fiction fans in frequent discussions and used on the Usenet which started in 1980. It was in common usage as "humble" in APA (Amateur Press Association) publications during the 1980s, and possibly earlier. [Cueball, Megan, and Ponytail stand together, talking.] Cueball: I thought the "H" in "IMHO" was "humble," but Buzzfeed ran a poll and "honest" won. Megan: That can't be true. Their readers are messing with us. [Cueball and Megan look at Ponytail.] Ponytail: Are you sure? I always used it to mean "honest." Megan: ...What?! [Close up of Cueball holding a phone. A box with usage of "IMHO" and "TBH" from Google Trends shows "TBH" suddenly rising in 2011, with a second spike in 2014.] Cueball: It was definitely "humble" in the 1990s. Cueball: Maybe people who picked it up after the rise of "TBH" in 2011 interpreted it as "honest" and used it that way. [Cueball, Megan, and Ponytail as before.] Megan: I can't get over this. What other wrong opinions do you have? Megan: The "G" in "G-I-F"? Ponytail: Silent. [Close up of Ponytail, with Megan talking from offscreen.] Megan: The "S" in "SMDH"? Ponytail: "Swallowing." Megan: The "G" in "OMG"? Ponytail: "Giantess" or "genitals." [Cueball, Megan, and Ponytail as before.] Megan: The Dress? Ponytail: Black and white. Megan: Is the database language "sequel" or "ess cue ell"? Ponytail: I've always said "squill." Cueball: Okay, the big one: how many spaces after a period? Ponytail: None; I use tabs. Cueball: OMG. Megan: Yeah, mine too.

Driving Cars

Driving Cars

https://www.xkcd.com/1990

https://www.explainxkcd.com/wiki/index.php/1990:_Driving_Cars

[Cueball stands in front of a car holding his hands together in front of him.] Cueball: Time to accelerate this giant machine up to terrifying speeds and steer it using my hands, which I am allowed to do because I took a 20-minute test in high school! [Caption below the panel:] Driving freaks me out.

This comic is about how dangerous cars are. Cueball observes that it is a giant machine, and that he is able to accelerate it up to terrifying speeds simply because he once took a brief driving test. Note that the length and complexity of a driving test varies greatly per country. 20 minutes would be fairly normal for the USA, but much shorter than what is required on most other Western countries. However, it should be noted that you sometimes have to retake the test if your drivers license has expired, so the "just because I took a twenty minute test in high school" part is partially incorrect. This is similar to other comics, such as 1075: Warning and 722: Computer Problems , where Randall comments on how some of our routine, everyday tasks are quite unusual when viewed from a reductionist perspective. This subject has been covered in the many comics about Self-driving cars . Although this comic is not directly about such cars, the reference to Cueball steering with his hands could be seen as being in contrast with letting a computer drive (which is much safer ). The joke is that driving is in fact one of the top five most common causes of death, yet many (most?) people do not think of driving as an especially "scary" or "dangerous" activity. The rest of the joke is in the title text, "It's probably just me. If driving were as dangerous as it seems, hundreds of people would be dying every day!" This statement is ironic, drawing attention to the fact that many people ( over 3,000 per day world-wide, about 100 per day in the USA) do in fact die in car crashes. These statistics indicate that driving is as dangerous as Cueball thinks it seems; it is not just him perceiving it that way. As a matter of fact, in most regions of the US, automotive accidents are the leading cause of death for people aged 18 to 35. It's also worth noting that a difficult-to-estimate number of people die prematurely as a consequence of pollution caused by cars. [Cueball stands in front of a car holding his hands together in front of him.] Cueball: Time to accelerate this giant machine up to terrifying speeds and steer it using my hands, which I am allowed to do because I took a 20-minute test in high school! [Caption below the panel:] Driving freaks me out.

Research Areas by Size and Countedness

Research Areas by Size and Countedness

https://www.xkcd.com/1991

https://www.explainxkcd.com/wiki/index.php/1991:_Research_Areas_by_Size_and_Countedness

[An X-Y scatter plot of research areas, written in gray font, where both axes have arrows in both ends. At the end of each arrow is a label. Above the left part of the X-axis there is a line which goes to a text about the meaning of the X-axis. Similarly there is a line to from the top of the Y-axis to a questions “asked” to those that study the given subject, their answers being somewhere between the two labels on the Y axis.] [The X-axis from left to right, text first and then labels:] Size of the thing you study Small Big [The Y-axis from top to bottom, question first and then labels:] "That thing you study - how many of them are there?" "We have a pretty good estimate." "We have no idea" [The research areas names are listed here below by sorting them into the four quadrants from top left to bottom right. In each quadrant the areas are listed after most left first, and then top to bottom for those at the same x position.] [Upper left quadrant (Small & count known):] Elementary particle physics Dentistry Shakespeare studies Ornithology Ancient Literature [Upper right quadrant (Big & count known):] Presidential History Marine Mammology Railway Engineering Geology Cosmology* (*Depends who you ask) [Lower left quadrant (Small & count unknown):] Pharmacology Microbiology Entymology Mycology [Upper right quadrant (Big & count unknown):] Botany Paleontology Exobiology Black Hole Astronomy Theology Sortable table with the coordinates in percent:

This comic is a scatter plot that ranks different research fields according to the precision of the knowledge of the number of the studied object (vertical axis) vs. how large (the size of) the studied object is on the horizontal axis. For instance, the facts pertaining to the number of United States presidents are well known (although the exact number is disputed in that Grover Cleveland is usually counted twice, because he served non-consecutive terms, so the official count exceeds the number of unique Presidents), so the study of their history is at the top of the Y-axis. This study is placed close to the Y-axis as the size of a president is about midway in size between the two extremes of the X-axis, elementary particles to the left (small) and the entire cosmos (cosmology) to the right (big). On the X-axis, Presidents are close to the middle. Both presidents and other larger life forms (as a research area) including extinct animals (paleontology) and exobiology are all close to the same central position just right of the Y-axis, with smaller animals like birds and insects just to the left of the Y-axis. But where the number of presidents is well known (aside from the dispute about Cleveland), then the number of exoplanet life forms (exobiology) is completely unknown (and would likely be affected by other disputes, such as whether something the size of Pluto counts as a planet) and thus it will be found at the very bottom of the Y-axis, since we have no idea if there are life elsewhere and if so how many places will it be and how varied. The 19 research areas are listed and explained in the tables below. In the title text, mathematicians may give a third answer that the concept of counting the things being studied is not reasonable, because the things are abstract or otherwise not discrete. There are many different types of math that blend into each other, and many have turned into separate sub-disciplines based on different interpretations of fundamental rules. As a specific example in geometry, different interpretations of how many lines you may draw parallel to another line through a given point has lead to hyperbolic (infinite parallel lines) and spherical (0 parallel lines) geometric systems that are just as valid (and valuable, in some contexts) as the more commonly known Euclidean (1 parallel line) geometry. As a specific example of the blending, number theory , set theory , and topology all interrelate and it is difficult to concretely say whether many theorems belong to one branch of math or another. For a table with the coordinates given in percentage for each research field, see the table in the trivia section This is the section with the small items with count known. This is the section with the big items with count known. This is the section with the small items with count unknown. This is the section with the big items with count unknown. [An X-Y scatter plot of research areas, written in gray font, where both axes have arrows in both ends. At the end of each arrow is a label. Above the left part of the X-axis there is a line which goes to a text about the meaning of the X-axis. Similarly there is a line to from the top of the Y-axis to a questions “asked” to those that study the given subject, their answers being somewhere between the two labels on the Y axis.] [The X-axis from left to right, text first and then labels:] Size of the thing you study Small Big [The Y-axis from top to bottom, question first and then labels:] "That thing you study - how many of them are there?" "We have a pretty good estimate." "We have no idea" [The research areas names are listed here below by sorting them into the four quadrants from top left to bottom right. In each quadrant the areas are listed after most left first, and then top to bottom for those at the same x position.] [Upper left quadrant (Small & count known):] Elementary particle physics Dentistry Shakespeare studies Ornithology Ancient Literature [Upper right quadrant (Big & count known):] Presidential History Marine Mammology Railway Engineering Geology Cosmology* (*Depends who you ask) [Lower left quadrant (Small & count unknown):] Pharmacology Microbiology Entymology Mycology [Upper right quadrant (Big & count unknown):] Botany Paleontology Exobiology Black Hole Astronomy Theology Sortable table with the coordinates in percent:

SafetySat

SafetySat

https://www.xkcd.com/1992

https://www.explainxkcd.com/wiki/index.php/1992:_SafetySat

[A prototype for a small cube-shaped "CubeSat" satellite, with labels on various components.] [Labeled on top:] Rare-Earth Magnets Bic Mini Lighter Software-Defined Radio (code editable via a public wiki) [Labeled on right:] Laser Pointers (fixed) Laser Pointer (Hubble-seeking) Ozone-Depleting CFC Spritzer [Labeled on bottom:] Celebratory Firework Volatile Epoxy Seal Filler (Guncotton) [Labeled on left:] Americium Corners Spark Plug Solar Panel (found) Batteries (eBay) Wet Sand Dispenser [Labeled from within drawing in white text on top of a black rectangle:] Crude Oil [Caption below the panel:] My CubeSat proposal was the first to be rejected for violating every design and safety requirement simultaneously.

CubeSat is a standard format for small satellites that can fit in a 10×10×10 cm format with a mass of less than 1.3 kg. They have been widely used by academics for research satellites, and by both small and large companies. CubeSats have been discussed both before and after this comic, in 1866: Russell's Teapot and 2148: Cubesat Launch . CubeSats are often launched as an additional payload on commercial launches but also deployed from the International Space Station at the Kibo-Module or other airlocks. All these satellites are orbiting the Earth in a low orbit and since they have no propulsion system they also become a part of space debris when they are out of control; Eventually they will reenter earth's atmosphere without any further hazard. Only a few days before this comic was released the first interplanetary CubeSats called Mars Cube One was launched together with NASA's probe InSight aiming to the planet Mars . One of Randall's influences in creating this comic may have been controversy surrounding a commercial launch of a sub-CubeSat sized pico-satellite from a launch site in India, after the company had previously been denied launch permission within the US, due to safety concerns. There are multiple safety rules to ensure that the CubeSat cannot damage the primary payload. However, the joke in this comic is that Randall 's design seeks to break as many rules as possible. Items clockwise from top left: Rare-Earth Magnets Violates CubeSat Design Specification Rev. 13 § 3.1.10. Rare-earth magnets are very powerful magnets that have a high likelihood of messing up the functioning of nearby electronics, like other CubeSats. Might also cause the CubeSat to stick to other satellites, as the M-Cubed and Explorer-1 Prime CubeSats did. BIC Mini-Lighter Does not conform to AFSPCMAN 91-710, Volume 3 § 10.1.3, in turn violates CubeSat Design Specification Rev. 13 § 3.1.7 Fire source, resting on the can of crude oil. The pressurized butane could also make the lighter burst, but in space without oxygen the lighter never would ignite. And even if the inside of the CubeSat contains some oxygen in weightlessness a flame would go out very soon, of course if it set off the crude oil or the guncotton then it would not matter, as the CubeSat would be destroyed. SDR/ Software-Defined Radio (Code Editable via Public Wiki) Violates Title 47 CFR Part 97 § 97.207(b), in turn violates CubeSat Design Specification Rev. 13 § 3.4.3.2.1 A radio which can be programmed to broadcast and receive in a range of frequencies, and formats. Software-Defined Radios are useful for development of new or modified wireless protocols, as well as for monitoring the raw waveform data of a transmission regardless of the protocols used. The radio in this comic is stated to run firmware which can be modified from a publicly editable Wikipedia-style webpage. Since anyone could change the radio's instructions, the radio could interfere with other satellites, or with the launch vehicle. This counts as a huge security risk, as anyone could edit it. Laser Pointers (Fixed) Does not conform to AFSPCMAN 91-710, Volume 3 § 8.2.2, in turn violates CubeSat Design Specification Rev. 13 § 3.1.7 These three laser points will effectively point in 3 different random directions, which is not safe for other objects around this Cubesat. It depends on the power of the laser pointers but, in general a laser over 5 mW can heat up and damage things given enough time. [ citation needed ] . Of course, with the satellite being in orbit it could potentially mess up the optical sensors of other satellites, but it would be a matter of chance. This could also be a reference to the book What If? , specifically the chapter Laser Pointer . Laser Pointer (Hubble-Seeking) Does not conform to AFSPCMAN 91-710, Volume 3 § 8.2.2, in turn violates CubeSat Design Specification Rev. 13 § 3.1.7 Aiming a laser at a visible light telescope is potentially destructive to the telescope in question by damaging its optical sensors. This is because CCD & CMOS image sensors are designed to detect finite light sources, concentrated & focused by an optical lens. Lasers produce high light levels well beyond the (comparatively) very low intensity light which astronomical image sensors are designed to detect; The energy of these excess photons can heat up the circuits between rows of photosensitive cells to the point where they overheat and fuse. For much the same reason, originates the phrase "do not stare into laser with remaining eye". Unlike the fixed laser pointers above, this one would track and aim a laser at the Hubble, with potentially disastrous results. CFCs/Ozone-depleting CFC Spritzer Does not conform to AFSPCMAN 91-710, Volume 3 § 10.3, in turn violates CubeSat Design Specification Rev. 13 § 3.1.7 Chlorofluorocarbons (CFCs) are fully halogenated paraffin hydrocarbons that contain only carbon, chlorine, and fluorine, produced as volatile derivative of methane, ethane, and propane. Freon is a common example of a CFC, and the use of CFCs has been linked to a depletion of the Earth's ozone layer leading many countries to ban their use. Thus spritzing CFCs in an area relatively close to the Ozone layer may be a bad idea. Celebratory Firework Violates CubeSat Design Specification Rev. 13 § 3.1.3. Does not conform to AFSPCMAN 91-710, Volume 3 § 13.2, in turn violates CubeSat Design Specification Rev. 13 § 3.1.7 Explosive fire source that could hit other satellites in the vicinity; Also potentially breaking the adjacent seal & igniting the crude oil behind it, turning it into crude oil that is also on fire. Could also set off the guncotton and result in an explosion that destroys the satellite. At the very least, the off-axis position of the firework within the CubeSat would most likely send the satellite into an uncontrolled spin, upon celebratory launch. Volatile Epoxy Seal Does not conform to AFSPCMAN 91-710, Volume 3 § 10.1.3, 12.1, in turn violates CubeSat Design Specification Rev. 13 § 3.1.7 Epoxy is a substance composed of long-chain molecules which exhibit very strong adhesive bonds. Many mixtures of epoxy are flammable & produce hazardous fumes when burned. If this particular epoxy seal fails, everything within splatter range gets coated in flammable crude oil. Crude Oil Violates CubeSat Design Specification Rev. 13 § 3.1.6 Does not conform to AFSPCMAN 91-710, Volume 3 § 10.1.3, in turn violates CubeSat Design Specification Rev. 13 § 3.1.7 Exxon Valdez oil spill , Deepwater Horizon explosion , Keystone Pipeline leaks ... need we say more? Of course the leakable volume would not be near those levels, but plenty dangerous nonetheless if it were to leak though a faulty seal or weld breakage or stress fractures. Containment and cleanup of such a leak would not be helped by the fact that such leakage could occur in orbit or even during launch. Oil spills in orbit might even present new and unexpected complications due to unusual behavior of liquids in vacuum and microgravity. Guncotton Does not conform to AFSPCMAN 91-710, Volume 3 § 10.1.3, in turn violates CubeSat Design Specification Rev. 13 § 3.1.7 A form of nitrocellulose ; an explosive. Could be set off by the firework, the crude oil, or the spark plug. Nitrocellulose does not work reliably in vacuum and possibly caused a failure of Philae space probe . Americium corners Does not conform to AFSPCMAN 91-710, Volume 3 § 9.1.1, in turn violates CubeSat Design Specification Rev. 13 § 3.1.7 Americium is a very dense and radioactive substance. Depending on the amount of americium involved, this alone could shoot the mass over the 1.3 kg mass limit. The isotope 241 Am is used in smoke detectors but also proposed for use in radioisotope thermoelectric generators in spaceflight. Spark Plug Does not conform to AFSPCMAN 91-710, Volume 3 § 10.1.3, 10.1.4, in turn violates CubeSat Design Specification Rev. 13 § 3.1.7 Fire ignition source, if connected to electricity; excess mass if not. The electrodes on the spark plug are next to the guncotton which could ignite if the spark plug fires. Additionally, sparks cause electromagnetic interference and electrical shorts. Solar Panel (Found) The quality of the solar panel and the power it produces would have to be investigated thoroughly before being cleared for space flight. Also, it isn't clear on the design exactly what, if anything, it is supposed to power, or if it is just excess mass. Batteries (eBay) The quality of batteries bought on auction sites can vary widely, and certain batteries exposed to conditions outside their design specifications can explode or leak corrosive acids . These batteries might also be connected to the adjacent spark plug. Non-rechargable commercial batteries may leak or explode if a recharge is attempted, so if this is the intention of the Solar Panel, these would escalate into an even greater risk. Wet Sand Dispenser Violates CubeSat Design Specification Rev. 13 § 3.4.3 Possible reference to the Kessler syndrome , which refers to a hypothetical situation wherein there are enough objects floating around in low earth orbit that collisions between objects might result in a "domino effect," each collision causing more collisions and breaking objects into smaller pieces of space debris, which increase the likelihood of further collisions. Wet sand exhibits a high grip:slip ratio, where the surface tension of the water tends to make particulates clingy. Sand (silica granules) can be very harmful to a wide variety of systems, due to its hardness & abrasive qualities. Depending upon the pattern of water sublimation in either shaded or sunlit zones, the exact behavior of various quantities of "wet sand" in low Earth-orbital space might be of interest to the designers of this and of other spacecraft. Title text Violates CubeSat Design Specification Rev. 13 § 3.4.4 Prongs that extend in the event of an unexpected sensor reading at launch could damage the rocket and/or nearby CubeSats/payloads. That the CubeSat reacts to an "unexpected" sensor reading - which could include any number of readings that aren't actually a problem - is also funny, as is the fact that this is described as "safely" securing the CubeSat and any surrounding CubeSats. Along with this, it is not unlikely that this CubeSat might be the source of any internal problem that might arise; in such a situation, having such a dangerous CubeSat further secure itself would be counterproductive, if spitefully entertaining. [A prototype for a small cube-shaped "CubeSat" satellite, with labels on various components.] [Labeled on top:] Rare-Earth Magnets Bic Mini Lighter Software-Defined Radio (code editable via a public wiki) [Labeled on right:] Laser Pointers (fixed) Laser Pointer (Hubble-seeking) Ozone-Depleting CFC Spritzer [Labeled on bottom:] Celebratory Firework Volatile Epoxy Seal Filler (Guncotton) [Labeled on left:] Americium Corners Spark Plug Solar Panel (found) Batteries (eBay) Wet Sand Dispenser [Labeled from within drawing in white text on top of a black rectangle:] Crude Oil [Caption below the panel:] My CubeSat proposal was the first to be rejected for violating every design and safety requirement simultaneously.

Fatal Crash Rate

Fatal Crash Rate

https://www.xkcd.com/1993

https://www.explainxkcd.com/wiki/index.php/1993:_Fatal_Crash_Rate

[Graphs are shown inside of a panel.] [Graph 1:] My fatal car crash probability based on my age [Label at 2018:] Now [Graph 2:] Overall US fatal crash rate per mile traveled [Label:] General safety improvements [Graph 3:] My miles traveled by car per year [Label after 2018:] Depends on job, where I live, etc. [Graph 4, below the previous graphs:] My estimated lifetime probability of being in a fatal car crash [Label pointing at late-2020s:] Point at which self-driving cars become safe and widely adopted, making crashes rare (assuming that happens) [Label pointing at a gray segment after late-2020s:] Fatal crashes avoided [Caption below the panel:] It feels weird to look at car crash statistics and wonder whether we'll all be able to stop driving before I'm involved in a fatal crash.

This is the second recent comic after 1990: Driving Cars on the subject of the dangers of cars. It combines general statistical correlations between age and safety improvements with fatal crashes. The graphs are: The final graph, ostensibly the product of the three previous graphs' probabilities, shows that Randall worries that he will eventually be involved in a fatal car crash unless self driving cars take over, which he believes would eliminate car related fatalities. He is of the opinion that they will take over, but that they might not do so quickly enough to 'save' him from the spike of age-related fatalities in later life. The comic includes three smaller line graphs along the top, and then a larger line graph, which is kind of a combination of the three smaller ones, at the bottom. A vertical dotted line is used on all these graphs to indicate "now", 2018; everything to the left of the graph has already happened (though the graphs are showing statistical history rather than actual history) and everything to the right is projected to happen, statistically. The first smaller graph, labeled "My fatal car crash probability based on my age", shows the likelihood he'll be involved in a car crash at different ages. The line doesn't start until slightly before 2000, probably when he first learned how to drive and started driving himself. He's not including when he would have been a child and a passenger, just when he is the actual driver. The two most dangerous ages to be driving are generally when you've first learned how to drive (and haven't yet mastered the skills or gained learned reflexes) and then again at an elderly age when your reflexes are slower and your senses become more limited (narrow field of vision/loss of peripheral vision, worse hearing, etc.). The middle smaller graph, labeled "Overall US fatal crash rate per mile traveled", lists how likely a fatal car crash is on a mile-by-mile basis, regardless of age. It used to be you were much more likely to have a fatal car crash in any given mile due to lack of safely features in cars in the 1970's. As more safely features were introduced and mandated, some to help prevent accidents (i.e. anti-lock brakes) and some to help make more of the accidents survivable (seat belts, air bags), overall safely has improved and is projected to continue improving. The third smaller graph, labeled "My miles traveled by car each year", is a simple graph of the distance Randall has driven every year. As he approached 2010, he was driving a lot more then when he first started, then life circumstances presumably changed so his need to drive diminished a bit, and now it's slightly increasing again. He has no way to predict future life driving needs, however, so the graph converges after "now" to include both gradually increasing as well as gradually decreasing driving needs. At an advanced age he'll probably mostly stop driving. The final, large graph, labeled "My estimated lifetime probability of being in a fatal car crash", combines these different factors into a smoother curve of gradually being safer (or at least not dying) while driving, with the possibility introduced, at an indeterminate time, that self-driving cars get to the point where they are both safe and widely adopted, at which point Randall expects the chance of a fatality to decrease to zero over a relatively short period of time (i.e. a decade). In the event the self-driving cars do not deliver in safely and/or are not widely adopted, the safety will gradually level off and then increase a bit near older age before dropping off again, but always with a distinct chance of fatality. As the title text points out, fixating to this degree on a single source of danger is unhealthy. But the more Randall fixates on the danger of car crashes, the safer (or maybe the less ) he drives, which reduces his chance of being in a fatal car crash. Note that Randall used to fixate on the danger of velociraptors, there is even an entire category based on his fear of them. If one were to become a professional driver and drive at 50 mph for 8 hours a day, 200 days a year, for 50 years - one would drive about 4 million miles - so one's risk of dying in a car crash would be much less than 1%. [Graphs are shown inside of a panel.] [Graph 1:] My fatal car crash probability based on my age [Label at 2018:] Now [Graph 2:] Overall US fatal crash rate per mile traveled [Label:] General safety improvements [Graph 3:] My miles traveled by car per year [Label after 2018:] Depends on job, where I live, etc. [Graph 4, below the previous graphs:] My estimated lifetime probability of being in a fatal car crash [Label pointing at late-2020s:] Point at which self-driving cars become safe and widely adopted, making crashes rare (assuming that happens) [Label pointing at a gray segment after late-2020s:] Fatal crashes avoided [Caption below the panel:] It feels weird to look at car crash statistics and wonder whether we'll all be able to stop driving before I'm involved in a fatal crash.

Repairs

Repairs

https://www.xkcd.com/1994

https://www.explainxkcd.com/wiki/index.php/1994:_Repairs

[Caption above the diagram:] How well something works After I decide to fix it [The comic shows a graph with a solid curve that decreases in 8 different sized steps from the top left to the bottom right. The X-axis shows time passes and gives the time from zero to five hours with 6 ticks with labels beneath. The Y-axis shows how well something works with 8 ticks, but only four of them labeled.] Works great Has minor problems Doesn't work Will never work again 0 hours   1 hour   2 hours   3 hours   4 hours   5 hours [The solid line has six labels with eight arrow pointing to different sections, two times the same label has two arrows pointing to different sections the first two places where the lines takes a step down, and the second to two plateaus on either side of a step. In total the arrows point four times on both steps and plateaus. Both the first and final plateau has a dot has added to the line, and the arrows point to those. Above the solid line there are three dotted lines going up from three plateaus just before the solid line takes a step down, the last two of these lines split up in two, with one going higher. At the end of each of these five dotted lines there is a sentence spoken. The solid line begins at the 2nd tick on the Y-Axis and finishes at the last. The three dotted lines going up ends up at the 1. tick on the Y-axis, for the last two there are also a line ending at the 2nd tick and 3rd tick respectively. Only the first label being above the first tick on the X-axis but the last three labels are all above the last tick on the X-Axis. Here is a list of all the labels in chronological order according to the position on the X-axis. For those that has the same time stamp the top one will be mentioned first. Those at the end of a line are indented:] I start trying to fix it "It just needed cleaning!" Take it apart "Fixed it!" "Well, at least it's not more broken than when I started." Take it apart more Watch YouTube instructional videos Take a deep breath and cut wires "That was heroic and I deserve a Nobel prize." "Well, it sort of works now." (Turn to other possessions) "...And let that be a lesson to you."

This graph depicts the sentiment created by the act of repairing something, depending on the time it took (x-axis) and the ensuing result (y-axis). The degree of triumph and exultation (expressed in sentences in quotes inside the graph) is strongly enhanced by the time the operation takes and is also positively correlated with the result (if any). Actions during the repair process are described in sentences without quotes. The conclusions are rather optimistic; the most negative feeling expressed (after the maximum time of repair with the minimum degree of success) is a threat against other objects that might have plans to break. The graph shows the main path most of his fixes apparently usually take (solid line) along with some variations they sometimes take (dotted lines). Projects usually start out with items that mostly work, but have minor problems. Occasionally they just need a cleaning (first dotted line). If that doesn't work, he takes them partly apart, and then there are times he's able to put them back together and get them to either work completely (one branch of a dotted line) or get it back to the condition it started out in (the other branch of the dotted line), at which point he doesn't tempt fate by continuing, knowing what's likely to happen if he continues messing with it. When it's still not working, he takes it apart more, starts doing less reversible things like cutting wires, and finally starts watching YouTube videos hopefully showing the right way to fix it, or at least how others fixed it. This takes it to a state just one step above "Will never work again", after which there can be several results. One dotted line shows it's restored to being fully fixed and he feels victorious and proud that all the hard work paid off, and he thinks he deserves a Nobel Prize for his efforts. The next dotted line is when he gets it partially working again, and gives up, satisfied to at least not have completely destroyed it even though it's a little worse than before. The third, main path result is total failure, which he could take as a personal failure but to which he instead responds with humor by admonishing the rest of his possessions not to develop minor problems otherwise the same total destruction might happen to them. This path ends up a partial step below "Will never work again" so it's unclear what that state is... maybe that's the "throw it away" state. The title text shows another excuse for failure. Nobody would spend five hours being a trash compactor. One could however claim to be separating the different parts for sorting into recycling bins or separating the parts that aren't themselves damaged by the process from those that will no longer be of use to anyone. This still doesn't have any tangible benefits for the one doing the sorting (although it might earn them points with the recipient). A similar sentiment was expressed in 349: Success . However, in Success, the computer would keep developing new problems and putting Cueball in worse and worse situations while in this comic it is just that Randall has increasing trouble fixing the issue as time wears on. [Caption above the diagram:] How well something works After I decide to fix it [The comic shows a graph with a solid curve that decreases in 8 different sized steps from the top left to the bottom right. The X-axis shows time passes and gives the time from zero to five hours with 6 ticks with labels beneath. The Y-axis shows how well something works with 8 ticks, but only four of them labeled.] Works great Has minor problems Doesn't work Will never work again 0 hours   1 hour   2 hours   3 hours   4 hours   5 hours [The solid line has six labels with eight arrow pointing to different sections, two times the same label has two arrows pointing to different sections the first two places where the lines takes a step down, and the second to two plateaus on either side of a step. In total the arrows point four times on both steps and plateaus. Both the first and final plateau has a dot has added to the line, and the arrows point to those. Above the solid line there are three dotted lines going up from three plateaus just before the solid line takes a step down, the last two of these lines split up in two, with one going higher. At the end of each of these five dotted lines there is a sentence spoken. The solid line begins at the 2nd tick on the Y-Axis and finishes at the last. The three dotted lines going up ends up at the 1. tick on the Y-axis, for the last two there are also a line ending at the 2nd tick and 3rd tick respectively. Only the first label being above the first tick on the X-axis but the last three labels are all above the last tick on the X-Axis. Here is a list of all the labels in chronological order according to the position on the X-axis. For those that has the same time stamp the top one will be mentioned first. Those at the end of a line are indented:] I start trying to fix it "It just needed cleaning!" Take it apart "Fixed it!" "Well, at least it's not more broken than when I started." Take it apart more Watch YouTube instructional videos Take a deep breath and cut wires "That was heroic and I deserve a Nobel prize." "Well, it sort of works now." (Turn to other possessions) "...And let that be a lesson to you."

MC Hammer Age

MC Hammer Age

https://www.xkcd.com/1995

https://www.explainxkcd.com/wiki/index.php/1995:_MC_Hammer_Age

[Cueball and White Hat are walking together.] Cueball: Want to feel old? MC Hammer just turned 40. White Hat: Wow. White Hat: I mean, I guess that's not too surprising, right? White Hat: It's been a long time. [Caption below the panel:] My hobby: Deliberately lowballing "Want to feel old" factoids to set up a bigger payoff later when they learn the correct number.

This is the first comic to combine the My Hobby series with the theme of listing facts that make one feel old . In the comic Cueball (as Randall , as it is his hobby) is asking White Hat if he wants to feel old. (This exact opening phrase was used by Megan in 1898: October 2017 ). Cueball doesn't wait for an answer, though like Megan did, but tells White Hat that MC Hammer just turned 40. Surprisingly, at first, this doesn't really make White Hat feel old, he actually feels this is rather normal (compared to his own age). MC Hammer is a pop rapper/singer who was most popular in the early 1990's for U Can't Touch This with the catch phrase Stop: Hammer Time , and shiny baggy pants often incorrectly referred to as parachute pants . So at first it seems that Randall's attempt to make White Hat feel old has failed miserably. However in the caption Randall explains that this is part of his hobby. By "lowballing" the facts to begin with he can make people feel really old when he tells them the truth, so they learn that the correct number (age/years ago, your age at the time etc.) is even worse than the first opening statement. In the title text he then tells White Hat the "truth": "Wait, sorry, I got mixed up--he's actually almost 50. It's the kid from The Karate Kid who just turned 40." This suddenly adds ten more years to MC Hammer's age, and the kid from the Karate Kid movies is already 40 years old. This likely makes White Hat feel old. In the original The Karate Kid , Ralph Macchio was the actor who starred as Karate Kid. The real blow, comes when White Hat (and most likely the reader), now intrigued goes home and looks these two people up on Wikipedia. Ralph Macchio was already much older than the kid he portrays in the movie, a school kid - he was 22 years old when shooting the first movie. On the day this comic came out, both MC Hammer and Ralph Macchio were 56 years old. And Ralph is the older one of the two being born in 1961, while Hammer was born in 1962. (In fact, Macchio is older now than Pat Morita , who played his mentor in The Karate Kid , was when that film was released.) So even in the title text, the corrections are both "lowballed" facts, so still preserving the maximum effect while adding more credibility to the claims, so people already start to feel old before the last 6 years is added to Hammer's age. Of course, this is assuming they do look it up, and if they believe Randall the first time, there is no reason to assume this will happen. However, then they probably already feel old from the first correction. Note that in the other make one feel old comics Randall did not apparently indulge in this new hobby of lowballing facts. As far as we can tell, those were all accurate for the time the comic was created. But if this is a new hobby, we may need to examine newer "feel old" comics extra carefully from now on. (If we want to feel even older that is.) [Cueball and White Hat are walking together.] Cueball: Want to feel old? MC Hammer just turned 40. White Hat: Wow. White Hat: I mean, I guess that's not too surprising, right? White Hat: It's been a long time. [Caption below the panel:] My hobby: Deliberately lowballing "Want to feel old" factoids to set up a bigger payoff later when they learn the correct number.

Morning News

Morning News

https://www.xkcd.com/1996

https://www.explainxkcd.com/wiki/index.php/1996:_Morning_News

[Megan, looking on a smartphone in her hand, and Hairbun are standing together and talk.] Megan: Every morning, before my eyes even focus all the way, I read a bunch of infuriating national news stories and bad opinions. I wonder what this is doing to my brain. Megan: It's probably not great. [Zoom in to the head of Hairbun.] Hairbun: Back in my day, we had to pay people to print out infuriating news stories and bring them to our door. And we waited until we had stumbled out to the kitchen to read them. Hairbun: Totally different. [Frameless panel, zoom out on both while Megan has lowered her hand holding the phone.] Megan: OK, fair. But newspapers at least had more local news mixed in, right? Hairbun: Yeah, true. [Same as last panel, except it has a border.] Megan: I bet they weren't full of bad opinions. Hairbun: Yyyyyes. Hairbun: All our opinions were good. It was a remarkable time. Hairbun: Please don't go check.

Megan is complaining to Hairbun about her easy access to infuriating national news stories and bad opinions (editorial articles and commentary) and worries that it may be having a negative effect on her, perhaps by promoting misinformation, by distraction, or by prompting adverse emotional reaction to content; she muses that, in some way or another, this habit is probably doing some sort of damage to her brain's wiring, training it to think in ways that are not necessarily good. While the capacity of the brain to change and adapt to a person's daily habits is, like most neurological phenomena, as yet not very well understood, it's clear that something of the sort exists--scientists refer to this capacity as " neuroplasticity ." Hairbun sarcastically tells Megan that things were different in her time, implicitly stating that access to infuriating stories via newspapers took only a tiny bit more time and effort during a morning routine compared to accessing them via the Internet. Megan counters this idea and says that while it is true that newspapers provided the sort of national news she is being provoked by, they also had much more local news mixed in (which may be of a lighter nature, sometimes referred to in a derogatory sense as "fluff" news pieces), to which Hairbun agrees. Megan also raises the point that bad opinions were not granted wide distribution. Hairbun is rather less quick to agree to this, and suggests that Megan not check that, revealing that Megan’s assertion isn’t entirely true. Indeed, before the Internet, newspapers were a common medium for expressing opinions, either by local columnists or average citizens via letters to the editor, and they, as with any body of opinions throughout history, were frequently noxious or ill-informed. This comic has a similar tone to 1348: Before the Internet in that it makes fun of the idea that life and society were better "in the good old days". The title text takes another jab at newspapers as a supposedly superior source of news. Supporting your local paper is generally considered a positive action, as it is often the best or only source for local news (national media can't focus on smaller areas, and radio/television often lacks print media's focus on investigative journalism). However, in recent years, many seemingly independent local newspapers in major cities have been bought up by financial groups rather than traditional publishing companies, and their effect on the industry as a whole has been controversial. Most notably, hedge fund groups often attempt to make newspapers profitable by cutting costs and downsizing , at the expense of quality reporting; critics call such hedge fund groups "vulture capitalists" who are throttling newspapers for short-term profit, without any thought of long-term viability or public service. The owners of the fund may also be unethical or controversial for other reasons. Thus, the standard well-meaning suggestion of supporting your local paper may no longer be good advice. [Megan, looking on a smartphone in her hand, and Hairbun are standing together and talk.] Megan: Every morning, before my eyes even focus all the way, I read a bunch of infuriating national news stories and bad opinions. I wonder what this is doing to my brain. Megan: It's probably not great. [Zoom in to the head of Hairbun.] Hairbun: Back in my day, we had to pay people to print out infuriating news stories and bring them to our door. And we waited until we had stumbled out to the kitchen to read them. Hairbun: Totally different. [Frameless panel, zoom out on both while Megan has lowered her hand holding the phone.] Megan: OK, fair. But newspapers at least had more local news mixed in, right? Hairbun: Yeah, true. [Same as last panel, except it has a border.] Megan: I bet they weren't full of bad opinions. Hairbun: Yyyyyes. Hairbun: All our opinions were good. It was a remarkable time. Hairbun: Please don't go check.

Business Update

Business Update

https://www.xkcd.com/1997

https://www.explainxkcd.com/wiki/index.php/1997:_Business_Update

[Beret Guy, Ponytail, Hairy, Hairbun and Megan sit around a table, left to right. Beret Guy and Megan are sitting on chairs at the ends. All others are behind the table with no visible chairs. All characters face Beret Guy.] Beret Guy: Quarterly reports are looking good. Beret Guy: Our office is full of cash, we're producing stocks faster than ever before, and our customers are experiencing rapid growth. Beret Guy: Any updates? [Closeup on Ponytail, facing left.] Ponytail: Bad news: many of our assets were liquidated this morning due to a thermostat glitch. Ponytail: Good news: the sink in the kitchen has stopped producing original content. [Same as panel one, but characters are facing Megan.] Beret Guy: How are our finances? Megan: Our biggest source of revenue is our ongoing project to transmute lead into gold. Megan: Our biggest expense is our project to transmute it back. [Closeup on Beret Guy, facing right, offset to the left of the panel. Two characters speak from off-panel right.] Beret Guy: Lastly, any luck getting the girl from The Ring to stop showing up in our video conferences? Off-panel person 1: No, but honestly, she's made some good contributions. Off-panel person 2: Yeah, I think we should hire her.

This comic shows a meeting at Beret Guy 's business (as seen in these other comics ). As usual, those in the business demonstrate a misuse of business terminology and take strange happenings within the business in their stride. Though maintaining a semblance of business-savviness through the use of many corporate buzzwords, it becomes clear that what is normally metaphorical in a usual boardroom meeting is here are quite likely meant literally. The Quarterly Reports, described as "looking good," may be literally physically attractive (rather than recording successful business dealings). Beret Guy's comment that "the office is full of cash" seems to be an ordinary comment at a glace, but him saying that the office contains a lot of money instead of has a lot of money implies that the office is literally full of money, like coins, dollar bills, twenty dollar bills, etc., and not simply economically well-off. Most businesses keep their money in banks; any business that keeps all their money insecurely in the office is either criminally shady or incompetent. "We're producing stocks [as in the stock market, a.k.a. shares] faster than ever before." Stocks are valuable, so from an outside perspective making more of them would create value. However, the humor of this situation is that in real life, creating shares from nothing would reduce the value of existing shares (as the combined value of stocks should add up to the total value of the company...so creating more stocks means each has to be worth less to make the addition balance out). This is ironic in that typically stocks represent the value of the company, rather than being the product being created. Alternatively, the company may be producing the leg restraints known as stocks . It's unlikely that there would be many people wishing to buy these stocks. Conversely, if what they are making is soup stocks, then it could be related to the 'rapid growth' (i.e., obesity) of the customers. "Rapid growth" is something a business is supposed to attain for itself or its userbase, not its individual customers. If the customers are not children they are likely very concerned by this rapid growth, as should be Beret Guy if the rapid growth is being caused by his business and its products. "Liquidating assets" typically means that assets are being sold off for money rather than being retained or used. Assets "liquidated" in a thermostat glitch, meanwhile, may have been literally melted ("turned into liquid"). It could also mean that their infrastructure is so hilariously messed up (and/or the assets so bizarre) that a simple glitch in a thermostat somehow resulted in the loss of a large amount of the company's assets. Note that this type of thing is not entirely unheard of, as shown by a hack of a thermostat in a casino that led to massive data loss in 2017 . "Original content" is a catch-all term for unique creative products created by a website, e.g. articles, videos or TV shows. However, it is not typically used to describe sinks, which only provide water. Since the business team regards it as a problem, this means the sink is likely leaking or backing up, possibly with polluted water or rotting food waste, or perhaps creating things one would not expect a sink to dispense or even to exist (depending on how "original" this original content is). Transmuting lead into gold was a goal of alchemists for many centuries. With modern nuclear technology, it is actually now possible to accomplish transmutation of lead into gold, and gold into lead. While the expense far exceeds the value of the gold produced by such methods, it seems plausible that, given Beret Guy's surpassing strangeness, his company may be successfully and cheaply transmuting large quantities of lead into gold and back again. Since gold is worth much more than lead in today's market, the first transmutation could indeed result in major profit, while the reverse would obviously result in major losses, and be a rather pointless undertaking for a typical, profit-oriented business. It is also worth noting that the "largest source of revenue" may not be producing much revenue at all; it can still be the biggest if there are no others. On the other hand, past experience with Beret Guy's business would indicate that this company is making plenty of money , though they aren't necessarily sure how . Alternately, Beret Guy may be speaking literally about their "biggest source of revenue," referring not to the amount of revenue generated, but to the physical size of the source itself. A facility capable of transmuting heavy elements would most likely be constructed around a large particle accelerator such as a synchrotron, and accelerators of this type commonly measure several kilometers in diameter. Such a facility would likely be the largest physical structure owned by a commercial entity. In the last panel, "the girl from The Ring " refers to Sadako Yamamura, the antagonist of the Ring series by Koji Suzuki , or her counterpart Samara Morgan from the American remake , who has been referenced by xkcd several times in the past — 396: The Ring for example. One of Sadako/Samara's supernatural abilities is to appear in television screens as well as exit from them into the real world. Beret Guy claims she has done this several times in their video conferences, which may be possible if someone has hacked their video feed to play footage from the 2002 movie. However, some of Beret Guy's employees then proceed to remark that she has made contributions to the meetings in question, implying that the image of Sadako/Samara is not only alive but sentient and communicating with the employees, rather than killing them as she typically does in her movies. It's also possible that Sadako/Samara is simply the recording from the series, and her contributions are just in keeping with the general tone of the company's video conferences. Either way, it would appear that Beret Guy's sheer eccentricity has affected his staff to the point that a digital spectre would not be an abnormal employee; they're also oddly nonchalant about a movie character appearing in the real world, and at Sadako/Samara's out-of-character behavior. The title text refers to the May 25 deadline to implement the European Union's General Data Protection Regulation (GDPR) ; this comic parodies a business meeting about what the company is doing to prepare for it. However, while normally the problem would be how to handle the customers' personal information that the company requires to retain in order to do business, in this case it seems the company does not require personal information at all, and instead, customers are sending them theirs on their own (and they refuse to stop doing it!). Even more bizarrely, Beret Guy was told by the EU (or at least, he thinks he was) that he is exempt because he is European royalty of some kind, which would give him sovereign immunity , but he wants to fix this problem anyway, just to be on the safe side. [Beret Guy, Ponytail, Hairy, Hairbun and Megan sit around a table, left to right. Beret Guy and Megan are sitting on chairs at the ends. All others are behind the table with no visible chairs. All characters face Beret Guy.] Beret Guy: Quarterly reports are looking good. Beret Guy: Our office is full of cash, we're producing stocks faster than ever before, and our customers are experiencing rapid growth. Beret Guy: Any updates? [Closeup on Ponytail, facing left.] Ponytail: Bad news: many of our assets were liquidated this morning due to a thermostat glitch. Ponytail: Good news: the sink in the kitchen has stopped producing original content. [Same as panel one, but characters are facing Megan.] Beret Guy: How are our finances? Megan: Our biggest source of revenue is our ongoing project to transmute lead into gold. Megan: Our biggest expense is our project to transmute it back. [Closeup on Beret Guy, facing right, offset to the left of the panel. Two characters speak from off-panel right.] Beret Guy: Lastly, any luck getting the girl from The Ring to stop showing up in our video conferences? Off-panel person 1: No, but honestly, she's made some good contributions. Off-panel person 2: Yeah, I think we should hire her.

GDPR

GDPR

https://www.xkcd.com/1998

https://www.explainxkcd.com/wiki/index.php/1998:_GDPR

[The picture shows a long text:] Privacy policy We've updated our privacy policy. This is purely out of the goodness of our hearts, and has nothing to do with any hypothetical unions on any particular continents. Please read every part of this policy carefully, and don't just skip ahead looking for sex scenes. This policy governs your interactions with this website, herein referred to as "The Service", "The Website", "The Internet", or "Facebook", and with all other websites and organizations of any kind. The enumeration in this policy, of certain rights, shall not be construed to deny or disparage others retained by the users. By using this service, you opt in to quartering troops in your home. Your personal information Please don't send us your personal information. We do not want your personal information. We have a hard enough time keeping track of our own personal information, let alone yours. If you tell us your name, or any identifying information, we will forget it immediately. The next time we see you, we'll struggle to remember who you are, and try desperately to get through the conversation so we can go online and hopefully figure it out. Tracking pixels, cookies, and beacons This website places pixels on your screen in order to form text and images, some of which may remain in your memory after you close the page. We use cookies to enhance your performance. Our website may use local storage on your device if we run low on space on our end. We may use beacons to call Rohan for aid. 3rd party extension This service may utilize 3rd party extensions in order to play the song Can U Feel It from their debut album Alive . Permission For users who are citizens of the European Union, we will now be requesting permission before initiating organ harvesting. Scope and limitations This policy supersedes any applicable federal, state, and local laws, regulations and ordinances, international treaties, and legal agreements that would otherwise apply. If any provision of this policy is found by a court to be unenforceable, it nevertheless remains in force. This organization is not liable and this agreement shall not be construed. These statements have not been evaluated by the FDA. This website is intended to treat, cure and prevent any disease. If you know anyone in Europe, please tell them we're cool.

This comic was released on the date on which the General Data Protection Regulation (GDPR) law went into effect. Most people will have already seen a large number of updated privacy policies in the week or two leading up to this law going active. And while xkcd would likely be outside of the jurisdiction that the law can enforce, it technically does fall within the scope of the law (as certainly EU citizens visit xkcd). This extra-territorial applicability is one of the major keys in this regulation and can be seen in more detail at the EU GDPR Information Portal . There are several references made to this law, but also several jokes are included about the way people treat privacy policies specifically, and user agreements in general. The comic is a joke privacy policy, with terms that no one would agree to under normal circumstances. In most cases, website users will use websites without reading the policies, potentially "agreeing" to something unexpected. The title text is a reference to Shakespeare's " The Tempest ", in which the witch Sycorax imprisoned the sprite Ariel in a cloven pine prior to Ariel's rescue by Prospero. As this clause cannot be escaped by anything short of restarting your computer, it may also reflect on how hard it often proves to be to opt out of privacy policy agreements and other forms to be filled on website, for all that they may appear optional. The fact that it appears as a title-text akin to a footnote, which a careless reader of the Privacy Policy may not notice at first glance, may also continue the joke of small but unexpected clauses hidden amidst a long-winded block of legalese, agreed to by users who haven't read them. [The picture shows a long text:] Privacy policy We've updated our privacy policy. This is purely out of the goodness of our hearts, and has nothing to do with any hypothetical unions on any particular continents. Please read every part of this policy carefully, and don't just skip ahead looking for sex scenes. This policy governs your interactions with this website, herein referred to as "The Service", "The Website", "The Internet", or "Facebook", and with all other websites and organizations of any kind. The enumeration in this policy, of certain rights, shall not be construed to deny or disparage others retained by the users. By using this service, you opt in to quartering troops in your home. Your personal information Please don't send us your personal information. We do not want your personal information. We have a hard enough time keeping track of our own personal information, let alone yours. If you tell us your name, or any identifying information, we will forget it immediately. The next time we see you, we'll struggle to remember who you are, and try desperately to get through the conversation so we can go online and hopefully figure it out. Tracking pixels, cookies, and beacons This website places pixels on your screen in order to form text and images, some of which may remain in your memory after you close the page. We use cookies to enhance your performance. Our website may use local storage on your device if we run low on space on our end. We may use beacons to call Rohan for aid. 3rd party extension This service may utilize 3rd party extensions in order to play the song Can U Feel It from their debut album Alive . Permission For users who are citizens of the European Union, we will now be requesting permission before initiating organ harvesting. Scope and limitations This policy supersedes any applicable federal, state, and local laws, regulations and ordinances, international treaties, and legal agreements that would otherwise apply. If any provision of this policy is found by a court to be unenforceable, it nevertheless remains in force. This organization is not liable and this agreement shall not be construed. These statements have not been evaluated by the FDA. This website is intended to treat, cure and prevent any disease. If you know anyone in Europe, please tell them we're cool.

Selection Effect

Selection Effect

https://www.xkcd.com/1999

https://www.explainxkcd.com/wiki/index.php/1999:_Selection_Effect

[Ponytail stands on a podium giving a presentation in front of a chart with some box plots.] Ponytail: Our research shows that compared to the overall population, people who agree to participate in scientific studies are significantly less likely to call the police to rescue them from our lab.

The title refers to the effect in scientific fields where instead of investigating the whole population (i.e. all cancer patients or all trees) only a subset is analysed. This is common practice as the analysis of all specimens is often impractical. However, special care needs to be taken when selecting the sample to ensure that it accurately represents the general population. Otherwise the results are misleading and do not reflect reality. For example if 1000 people are asked about the numbers of cars they own but all live in a city the results cannot be generalised to the whole country. This is called the selection bias . If non-human subjects are studied this can be avoided by randomising the selection process, but this is not possible with humans as they cannot be forced to participate in a study against their will. For example, if people are asked to participate in a study about their political views it is likely that the responders care about politics while people with no clear opinion do not bother to respond. This is called the self-selection bias . Ponytail says that people who agree to be in a study at their lab are less likely to attempt to escape. The only way Ponytail could have come to this conclusion is if she compared those people to people who did not agree to be in the study. This implies that Ponytail has recently kidnapped people for a study, and that most of the people she kidnapped called the police, as one should do when being kidnapped. This makes sense, since if you agreed to the study, you know why you are there, while if you didn't, you may have been kidnapped. As Ponytail presents this as a finding, it appears that she was attempting to establish a protocol for randomised selection of human subjects and comparing it to the normal selection process. The comic shows Ponytail being allowed to present the results of this study at a conference; reputable scientific journals and conferences should not legitimize studies that clearly violate their ethical norms, such as by failing to obtain informed consent from human subjects before experimenting on them. Unfortunately, involuntary studies are published and presented, like this 2014 Facebook's emotional contagion study . It is not clear how many people who did agree to participate may have attempted to call the police for assistance regardless; compare the Stanford Prison Experiment . This is similar to previous comics where obvious things are presented in obfuscated, scientific ways (e.g. 1990: Driving Cars ). Of course, any study of the way people behave when being kidnapped for scientific experiments would inherently involve kidnapping them. Therefore there is no way this kind of research could be done in an ethical fashion. The title text refers to a technique that measures brain activity, called Functional magnetic resonance imaging (fMRI) . Of course it's much more likely that people who did not sign up will resist and escape before the scan is complete. [Ponytail stands on a podium giving a presentation in front of a chart with some box plots.] Ponytail: Our research shows that compared to the overall population, people who agree to participate in scientific studies are significantly less likely to call the police to rescue them from our lab.

xkcd Phone 2000

xkcd Phone 2000

https://www.xkcd.com/2000

https://www.explainxkcd.com/wiki/index.php/2000:_xkcd_Phone_2000

[The comic depicts a smartphone showing many uncommon features. The front view shows a mouse cursor and a circle in the middle. The side view reveals the circle as something like an old photo lens from 1900 extending far above the surface and four large buttons (camera lenses) at the rear. The third view is from the top and just mentions a "hollow ground." The bottom view looks like as it was opened by a can opener and shows a big USB connector and on the right a small black connection.] Dockless Silent Quad camera takes four copies of every picture Front-facing camera obscura 3D facial contour analysis shows you a realistic preview of your death mask Sponsored pixels Front and rear pop-out grips Humidity-controlled crisper Antikythera mechanism New York Times partnership: all photos taken with camera app are captioned in real time by reporter Maggie Haberman Spit valve Standard USB connector Coin purse-style squeeze access Hollow-ground Absorbent Keyboard supports dynamic typing Backflow preventer Swiss Army partnership: folding knife (unlocks only if Switzerland is invaded) 100% BPA-free PCB construction AMOLCD display (7-segment) Runs on battery for the first 6 hours, then uses gasoline Sharpie® dual stylus (dry-erase + permanent) Mouse cursor Introducing The xkcd Phone 2000 We're still hoping this sounds like a futuristic number®®™®©™ ® The stylus was previously called 'permenant'. This was later corrected, to permanent. You can still see the original image here

This is the seventh entry in the ongoing xkcd Phone series , and once again, the comic plays with many standard tech buzzwords, and horribly misuses all of them, to create a phone that sounds impressive but self-evidently isn't to even the most ignorant customer. The previous comic in the series 1889: xkcd Phone 6 was released 8 and a half months before this one, and the next comic 2377: xkcd Phone 12 was released five months later. This time a nonconsecutive version number is used to match the milestone comic number 2000. List of features (clockwise from top-center): The tagline for the phone says that the marketing team hopes that 2000 still sounds like a futuristic number. It was common for a time to have futuristic science-fiction take place on or around the year 2000 (e.g. 2001: A Space Odyssey, Knight Rider 2000, Death Race 2000, Space: 1999), and many devices marketed in the late 20th century had a "2000" as part of their product name in order to sound futuristic. However, since the year 2000 was 18 years ago at the time of this comic's publication, this is no longer the case. The number 2000 also represents the fact that this is the 2000th xkcd comic. The nonsensical trademarking of xkcd Phone slogans has become even more pronounced: as well as the inapplicable-as-ever copyright symbol, the slogan is listed three times as a registered trademark and twice as an unregistered one – and the second of those trademark signs is itself trademarked. The title text refers to Retina Display , a term used to describe Apple products with higher pixel densities. The xkcd Phone marketing team would be unable to use the term due to Apple's having registered it as a trademark, as it would be a copyright violation. Additionally, the central fovea region is a portion of your eye's retina containing the most densely packed photosensitive neurons (confusing the biological retina with the electronics display of the same name). Foveated rendering is a genuine computer graphics technique intended to increase performance by rendering with higher quality to the regions of the display where the user is looking, and lower quality at the edges of vision; it is expected to be useful for virtual reality (one of the uses for cell phones) as a way to deal with the required high pixel densities while managing power consumption. There are displays with variable density, in specialist uses, but such a feature is not practical in a phone because the whole area of the display is typically useful and needs to provide high resolution (as the user's eye moves across it). Also, hundreds of pixels per inch is not considered a very high resolution, as a full-hd smartphone has 440.58 pixels per inch . [The comic depicts a smartphone showing many uncommon features. The front view shows a mouse cursor and a circle in the middle. The side view reveals the circle as something like an old photo lens from 1900 extending far above the surface and four large buttons (camera lenses) at the rear. The third view is from the top and just mentions a "hollow ground." The bottom view looks like as it was opened by a can opener and shows a big USB connector and on the right a small black connection.] Dockless Silent Quad camera takes four copies of every picture Front-facing camera obscura 3D facial contour analysis shows you a realistic preview of your death mask Sponsored pixels Front and rear pop-out grips Humidity-controlled crisper Antikythera mechanism New York Times partnership: all photos taken with camera app are captioned in real time by reporter Maggie Haberman Spit valve Standard USB connector Coin purse-style squeeze access Hollow-ground Absorbent Keyboard supports dynamic typing Backflow preventer Swiss Army partnership: folding knife (unlocks only if Switzerland is invaded) 100% BPA-free PCB construction AMOLCD display (7-segment) Runs on battery for the first 6 hours, then uses gasoline Sharpie® dual stylus (dry-erase + permanent) Mouse cursor Introducing The xkcd Phone 2000 We're still hoping this sounds like a futuristic number®®™®©™ ® The stylus was previously called 'permenant'. This was later corrected, to permanent. You can still see the original image here