Well-Ordering Principle

Explanation:
In the comic, Megan has found a genie lamp. A genie (or Jinn ) in a lamp is a supernatural, immortal being from many fairy tales, the most well known that from Aladdin , who grants one or more wishes to the person who frees it, such as by polishing or opening the lamp. Instead of wishing for multiple wishes, flight, money, or other "traditional" wishes, Megan instead wishes to see the worst Marty McFly Halloween costume.
Marty McFly , played by actor Michael J. Fox , is a main character of the science fiction film about time travel Back to the Future , which was released, we are reminded , over thirty years ago, starting a series of sequels. The films are popular, so many people dress up as McFly or Doc Brown, the other main character, on Halloween , a holiday on October 31 when it is traditional in the USA to wear different costumes . McFly's outfit in the original film consists of little more than an orange vest, jean jacket, checkered shirt, jeans, and sneakers. It would seem difficult to get this wrong.
In the final panel, the genie questions why she would wish for something so mundane, when he has the power to grant wishes beyond her wildest dreams. Megan, being savvy of tropes, used in fiction since biblical times, points out that encounters with wish-granting entities often turn out to be traps. Genies in fiction will often interpret wishes in ways the wisher did not intend, and particularly mean-spirited ones will twist a mortal's desire into their own personal hell . Even when the wish-granting entity isn't malicious, they're often portrayed as carrying unintended consequences, such that extremely consequential wishes become extremely dangerous. So Megan tries to play it safe by wishing for something innocuous and with little room for harmful side-effects.  Unfortunately, Megan appears to have forgotten the overarching trope: all wishes can be twisted against the wisher.
The genie may also be reluctant to fulfill the wish due to the insurmountable practical difficulties of fulfilling such subjective, ill-defined request. The well-ordering principle is a mathematical fact stating that every non-empty set of positive integers contains a least element. This principle would apply to Megan's request if there was guaranteed to be an absolute worst costume of Marty McFly. However, subjective preference , while reflexive and transitive , is not well-founded (or symmetric or necessarily antisymmetric or (semi-)connex for that matter) and is therefore considered to be a preorder , also called a quasiorder. This means that the genie may not be able to fulfill Megan's wish if the selection is based on the preferences of any one person. For example, the genie may have no opinion on the quality of any McFly costume, or might judge them on criteria completely different from Megan's. Her own criteria might apply to some pairs of costumes but not others, leading to ambiguity as to which is the worst, and no way to say whether any of the candidate possibilities are as bad as the others.
While Megan isn't explicitly wishing for a common or widely-shared opinion , the title text contemplates organizing a "nationwide" search. People's preferences can be combined, such as with a mean opinion score which, while not strictly well-ordered, is usually able to identify a single worst costume, or at least a set of costumes tied for worst place according to aggregate subjective preferences. There are many other ways to combine preferences (e.g. voting) but none of them meet all of the criteria considered desirable, as demonstrated by Arrow's impossibility theorem . There is no way to exclude the possibility that even an omniscient and omnipotent genie might be technically unable to fulfill the wish, at least without, for example, changing one or more persons' preferences or modifying the space-time continuum to retroactively change the quality of some costumes of the past. The genie could fulfill the wish by showing Megan every McFly costume ever worn, which would necessarily show her the worst by any possible definition, but could be the trap she was hoping to avoid because viewing all the "hundreds of thousands" would take an inordinately long time.
The title text may explain why Megan is interested in this wish: any means available to her would be restricted to a geographic area's (nationwide) photographs or drawings from memory. It is likely the worst costume was either never photographed, or isn't remembered accurately by those who saw it (it is "lost to time" -- which usually is just a figure of speech, but may actually be literally true in this case given the Back to the Future series' central theme of time travel). By asking the genie to show her, she might be able to see the truly worst costume without being restricted to only those for which evidence remains.  Such a wish fulfillment might even require actual time travel to the time and location where the costume existed. The title text can also be interpreted as Randall's wish to know about the worst costume. So this is not Megan but Randall who has the wish to see this costume. The best we can do today is to look through all the available photos of McFly costumes. But even if one of those could be agreed upon to be the worst, there is no guarantee that there is not even worse versions that is not documented for posterity. In this interpretation, what Randall really would like is to use a dangerous genie wish to get around these difficulties.
An additional, subtle pun plays on the word "well". In European folklore, water wells are often associated with spirits which may grant wishes, similar to genies. Thus, Megan's explanation of why she made a simple request of the genie is a statement of her "well-ordering principle"; her principle for ordering wishes from wells. (See also the Well series ).
[Megan rubs a lamp held in her hands. A genie appears from the end of the lamp. The genie resembles the top half of Cueball's body, with a head, torso, and crossed arms, but with a squiggle representing a puff of smoke in place of his legs.] Genie: Greetings, mortal.  You have freed me. I will grant you one wish. Megan: Hmm.
[Megan holding the lamp to her side. The genie is off-panel.] Megan: It's been over 30 years since Back to the Future came out.  Since then, probably hundreds of thousands of people have tried to dress as Marty McFly for Halloween. Genie: OK, and?
[Megan, holding the lamp to her side, talking to the genie, who is floating in the air.] Megan: Of those people, one of them must have done the worst job. Megan: My wish is to see their costume.
[Megan still holding the lamp and talking to the genie. The genie is exasperated, and has his hands raised.] Genie: Not a billion dollars? Flight? Infinite wishes? Megan: These wish things are always traps. Megan: Just show me the worst McFly and we'll call it even.


How to Send a File

Explanation:
Similar to 2190: Serena Versus the Drones , this is another teaser ad for Randall's new (at the time the comic came out) book, How To , due to be released a week from this comic's release, on September 3, 2019. This also prompted a change to the xkcd Header text .
The comic shows an image from of one of the chapters, and containing being a link to a larger piece of that chapter, or perhaps the entire chapter.
This comic discusses transferring files, previously discussed in 949: File Transfer and in what if 31 . The snippet from his book that is shown in this comic shows scissors cutting off the (top) screen of a laptop, presumably as a way to give the "bottom" portion to someone for file transfer. This is probably not a good idea. [ citation needed ]
The chapter linked to shows other methods of getting your files to another person and, in fact, explicitly states that breaking a computer to send files is not a good idea.
The title text hints at other amazing content in the upcoming book, including discussion of butterfly migration (does it cause predictable tornadoes in Kansas? Can they carry coconuts to England?). It also threats that using the books idea for file transfer  will make sure you will never see those files again, i.e. they will be lost for good if you try the book's method at home.
The chapter preview, that the comic links to, discusses using butterflies as a method of sending files from one person to another on the form of flash media attached to butterflies, or encoded in DNA, and goes pretty in depth into these particular methods of data transmission as opposed to the more traditional methods that are detailed in traditional computer science books.
[Randall, depicted as Cueball, stands with his arms spread out] Randall: It feels weird that it's 2019 and yet I still sometimes find that the easiest way to move a file around is to email it to myself.
[Randall has raised a hand to his chin,] Randall: If only there were a better way...
[A picture of Randall's new book is shown to the left of the text. The book is black with large blue text and smaller white text. On the book cover, in white drawings, are seen Megan with a ladder and White Hat. Both are looking up on Cueball who is floating in the air with a quadcopter drone beneath either leg, trying to plug in an electric light bulb in a naked lamp hanging down near him. It seems he has already removed the broken light bulb, as he has one in both hands. And now he tries to put in the new one. The blue text stating title and author can be read but not the white trext. The "blog.xkcd.com" link is in link blue color.] Book: How To Book: Randall Munroe My new book How To is out next week! If you want to learn how to send data, you can visit blog.xkcd.com for a sneak preview of Chapter 19: How to Send a File
[Beneath a heading are three pictures next to each other of a laptop computer. The first picture shows a regular laptop computer, with a labeled arrow pointing to the lower half of the computer. The second picture shows the laptop in a lighter outline, with scissors instructing to cut horizontally on a dotted line across the middle of the laptop. The third picture shows a laptop in two pieces cut over between the screen and the rest. There is a very jagged edge on both parts, which has been moved away from each other.] Exclusive advice from How To: When sending a file, it helps to know which part of your device the file is stored in. Label: Files are usually in this part


Dockless Roombas

Explanation:
In this comic Cueball discovers two Roombas outside, and Megan explains that they are dockless Roombas for rent. Cueball is confused, but then Beret Guy walks in, activates one with an app on his smartphone , and rides away standing on it.
A Roomba is a small automated (robotic) vacuum cleaner designed to clean a room or other bounded area by repeatedly and automatically going over the floor, vacuuming, until it has made multiple passes, and either runs low on power or is turned off.  The "intelligence" of various models can vary from relatively random operation with basic techniques to get around obstacles, to models that generate a general mental map of the area and contents and attempt to be deliberate in passing over all reachable areas.  A Roomba generally includes a recharging "dock", which it can find and automatically connect with when it gets low on power, allowing it to recharge and perhaps automatically begin another round of cleaning. Roombas are a recurring theme on xkcd. In 1193: Externalities it was Ponytail that drove a Roomba. And in 1486: Vacuum Beret Guy flew on a regular vacuum cleaner.
A dockless scooter is a system of sharing personal scooters whereby they can be left anywhere for someone else to use, rather than returned to a particular home location. They are typically activated via a smartphone app. The term "dockless" in the name refers to the fact they have no predefined home, or place to dock. Like a Roomba, they do need recharging, but no special station is needed for that -- anyone can pick them up and recharge them overnight from a standard power outlet, receiving a fee from the scooter company for this service. In the past several years they have become popular in many large cities around the world. Scooters have recently been featured in 2188: E Scooters .
The humor here is replacing the scooters with Roombas, which people would then ride.  There are multiple problems with this idea:
The title text refers to the controversy in many cities surrounding dockless scooters, which can be dangerous to pedestrians when in use and can block sidewalks and driveways when not.  Dockless scooters were introduced in many cities before there were any regulations about scooter use, with some critics claiming scooters exploited loopholes in existing law and regulation, and leading some cities to pass legislation to specifically ban or curtail the use of dockless scooters. Here it is the Roombas that exploit loopholes in those scooter laws, which initially bothers city officials before they realize the positive benefit of the Roombas cleaning their streets as they are ridden.
[Cueball and Megan walk in from the right and sees two Roombas on the ground in front of them.] Cueball: Are those... Roombas? Megan: Yeah, the dockless rental apps have really taken off.
[Cueball stops and turns to look at Megan, who has also stopped, as Beret Guy comes walking in from the left with his smartphone in his hand.] Cueball: What?
[As Cueball and Megan turn to look at Beret Guy, he stops between the two Roombas, looking down at the Roomba to his left. He taps his smartphone and the Roomba makes a sound.] Smartphone: Tap tap Roomba: Unlock
[Beret Guy is squatting down on the Roomba as it drives him away, while Cueball and Megan turns to stare after him,] Roomba: Whirrrr


Nice To E-Meet You

Explanation:
In this comic, Cueball is considering how to greet someone online.
At first, Cueball considers simply saying "Nice to meet you!", a typical greeting used when meeting someone in person. However, he notes that since the introduction is taking place electronically, saying that he is actually "meeting" them is inaccurate; he duly discards the greeting.
Next he considers replacing the word "meet" with "e-meet." The use of " e- " as a prefix for anything related to electronics was a popular naming trend in the early 1990s, such as eWorld , eBay , and as a standardized shorthand for electronic mail . Earlier cyberpunk novels, such as 1984's Neuromancer , did not use the "e-" prefix, as they were written before that linguistic trend, while the prefix generally fell out of fashion by the 2000s. Cueball using the phrase "e-meet" thus sounds anachronistic to the 1990s, and he recognizes it, discarding his greeting again.
He then decides that he needs to throw off the shackles of normal conversation and simply "be normal." Being a geek, Cueball therefore writes up a long-winded exposition of how strange electronic communication actually is in terms of the photons being projected by the computer screen, comparing it to his hands touching the receiver's eyes, then concludes the greeting with a simple "Anyway, hi." This might be off-putting to a friend that Cueball had just now met. This makes it funnier that Cueball believes he just "nailed" his greeting; he clearly has no idea what he is doing.
The title text continues the theme of "his hands touching the receiver's eyes"; Randall is talking about how as a construct that your mind makes, he  is now "inside your head"-- and taking it that statement to its logical conclusion, he "wants to get out."
The comic discusses how adhering to conversational convention during social interactions can be quite difficult, especially with the advent of new technology. Social awkwardness is a recurring theme in xkcd.
Advice has been written regarding the topic of whether to use "Nice to (e-)meet you" and possible alternatives, e.g. by Forbes , Huffington Post and Grammarly . The consensus seems to be that "Nice to meet you" is fine, though a bit cliche.
[Cueball is sitting at his desk on an office chair, while typing at his laptop. The line he is writing on the computer is shown with white text in a black box up at the top of the panel while his thoughts shown in a thought bubble with small bubbles going to it from his head.] Text: Nice to meet you! Cueball [thinking]: That sounds weird; we’re not actually meeting in person. Laptop: Type type Laptop: Delete delete
[Same setting:] Text: Nice to e-meet you! Cueball [thinking]: What is this, a 1995 cyberpunk novel? Laptop: Type type Laptop: Delete
[Cueball stops typing and leans back resting an arm on the back of the chair while looking at laptop, no black box shown.] Cueball [thinking]: OK. Cueball [thinking]: Chill. Cueball [thinking]: Just be normal.
[Cueball resumes typing a much longer text in two black boxes, one large with five lines of text, and a small below with one line.] Text: It’s weird to think that the words I’m typing will be projected onto your retinas. It’s like my hands are touching your eyes. Text: Anyway, hi. Cueball [thinking]: Nailed it. Laptop: Type type


Game Show

Explanation:
Many shows have situations where the participants are asked hypothetical questions. A common hypothetical question asked to ascertain what someone considers most important to them is the one item they would take to a deserted island -- to make the best of a boring situation.
Black Hat is on such a game show, and he does his best to undermine the intent of the question. Instead of answering with a favorite item -- such as his favorite album or book -- he lists various things (see below ), which he doesn't own and apparently expects the show's producers to provide him, starting with somewhat reasonable means of escape (e.g., a plane) to increasingly absurd items that appear to be chosen solely based on how difficult they would be to actually provide (e.g., the entire Atlantic Ocean). The items appear to follow Black Hat's stream of consciousness, starting with a boat, then a plane, then a distinctive plane, the bones of the pilot of that plane, the internal structure (similar to bones) of the famed landmark Statue of Liberty, etc.
The title text reveals that the game show has ultimately acquiesced to one of Black Hat's wishes in a way: the dog leash mentioned would allow him to water-ski home, though such a dog leash is implausible (for example, a dog leash from San Francisco to Hawaii would be over 2000 miles long).
[Cueball, Black Hat, and Megan are game show contestants standing behind lecterns with Hairy standing in front of them as the game show host. Black Hat, standing in the middle of the three, is holding a finger up while speaking.]
Black Hat: A boat. A plane. Amelia Earhart's plane. Amelia Earhart's skeleton . The Statue of Liberty's internal support frame. The Crown Jewels. This show's entire television audience. The Greenland ice sheet. Earth's north magnetic pole. Black Hat: Am I in the Pacific Ocean? Black Hat: If so, the Atlantic Ocean.
Hairy: Uhh. Hairy: Our producers are going to need some time on this one.
[Caption below the panel:] The game show realized that they should have added some restrictions to their "take any item to a deserted island" challenge, but it was too late.


Throw

Explanation:
This is an interactive comic made to celebrate the release of Randall's new book, How To . The comic is based on a chapter in the book.
As the comic celebrates the book, which was released on Tuesday, September 3rd, 2019, the comic was thus also released on a Tuesday to coincide with the release day, replacing that week's normal Wednesday release. This was the same timing used for another of Randall's book releases, when 1608: Hoverboard came out on the Tuesday when Thing Explainer came out. Although the Hoverboard comic is much more complex than this one, they are both dynamic and interactive , with animations a part of them. Also the xkcd Header text changed to promote the release creating a large combined promotion of the book during the three full days the comic was on the front page (see more here ).
In this comic the viewer can select a thrower and an object to be thrown, see this table , and get an animation of how the selected throw would work out, along with an estimated distance of the throw (both in the SI unit meter (m) and in other very arbitrary units; see this table below) if the throw was possible. Impossible throws include those where the thrower is not strong enough to throw the object, or when the thrower tries to throw themselves, which is possible as four "objects" are also listed as throwers, most prominently George Washington . As the comic picture above cannot show all the possible selections in the two windows, pictures of all can be found here
The formula/guideline is apparently based on chapter 10 from the new How to book, see more under Formulas .
It seemed though, that there was a special case to the calculations with Thor's hammer ( Mjolnir ). Because this comic obviously refers to the Thor from the Marvel universe , played by  another  possible thrower, Chris Hemsworth in the Marvel Cinematic Universe , and his hammer , which is enchanted such that only those deemed "worthy" are able to lift it. As such, despite its mass in principle being liftable by many of the characters, only Thor, God of Thunder (who is canonically worthy), is able to throw it. Also Thor is the only one who uses furlongs to measure his distances among the standard throwers. However, it is not a canonical part of this comic that only he can throw it, and its mass is not realistic, see more below.
Originally , when the comic was just released, there where only 7 throwers and 15 things to throw, giving a total of 105 different combinations; see the table below. But only Thor can throw all 15, with three of the objects (George Washington, Thor's hammer, and the car) unthrowable by any of the other throwers. The smaller critters can throw only a few things, so the total number of throws is much less than 105. Still, there is an animation for all 105 combinations, but with no throw distance for many of these.
But already on day one the comic was out, a new thrower was added with the standard name "You", and this person, Knit Cap , was also added to the objects that can be thrown increasing the number of throwers to 8 and objects to be thrown to 16. However, it would not be true to say that the number of options now would be 8 x 16 = 128, since the "You" can be customized when selecting it in the throwers menu (but not when selecting You in the object menu). When doing so a new window called Custom thrower will open up over the comic. The "You" option can then be customized by changing the name (from the default "You"), and defining the height (default 5.8 ft = 1.77 m) and weight (default 160 lb = 72.57 kg), where ft (feet) can be changed to m (meter) and lb (pound) can be changed to kg (kilograms). But when doing so the window will not correct the number from feet to meter etc. but stay the same.
Below the above options there is line with four persons above it, defining a scale of athleticism , the default second option being the drawing of "you" which represents Decent form (i.e. a normal person).  The first on the scale is Black Hat , who thinks moving things is for suckers, thus representing minimal athleticism. "You" in second position is in decent shape and pretty good form, representing decent athleticism. George Washington in third position represents extremely high athleticism, and as he states he threw so well they made him President. Finally the fourth position, representing a champion athlete, shows a person with a helmet with chin strap and goggles who states that he trains 36 hours a day by using a time machine. It is thus indicated that such athletes can only be so good by training more than is possible; for instance, if he travels 24 hours back every day, he could use 12 more of these to practice, making it 36 hours on that "normal day" and he would then still have 12 hours to eat and sleep/restitution before his next 36 hours training pass.
Changing away from the decent "You" to one of the other three characters on the athleticism scale does not, however, change the character used for the animation, which stays the same. But still this gives a very large number of different "yous" to both throw and be thrown.
A self-created character, unrealistically tall and heavy well over the human records for height ( 272 cm ) and/or weight ( 635 kg ), can actually be able to throw Thor's hammer (For instance 4m and 1000 kg, see more here . So it is not because it is magically inclined to only be thrown by Thor, it is just that the weight is set to 2000 kg, and only Thor of the standard characters have the strength (1000 times normal human strength) to throw such a heavy object. But if the "You" is big enough, the athletic difference with Thor will be compensated by sheer weight and height. See this table of data from the comic for the above numbers.
Interestingly, Thor can throw a squirrel 257 meters.  If a Custom Thrower is created, and they are 200 meters tall and 150 KG, they can throw the squirrel 256 meters (1 meter less than Thor).  Thor can throw an acorn 136 meters, and the Custom Thrower will throw it 133 meters.  Now, Thor can throw Thor's Hammer 19 meters.  The Custom Thrower can throw it 44 meters!  Apparently there is more to the enchantment of Thor's Hammer than meets the eye, as it would have been expected that if Thor can throw a squirrel and an acorn farther than an extraordinary human, then certainly he could throw his own enchanted Hammer a longer distance. This is, of course, because the Custom Thrower now throws from much higher than Thor.  As to why the height doesn't affect the acorn or squirrel throwing distance in the same way it does Thor's Hammer, we'll leave that to you, the reader.
The title text refers to throwing a party (a colloquial synonym of hosting a party) and first makes the assumption of actually giving hints for giving a party, and then switches to suggest a mechanism to literally throw a huge object, such as a house with a party going on inside. An aircraft steam catapult is a mechanism to launch aircraft from ships, typically used on aircraft carriers.
Many of the items, even if technically possible to throw, may not be able to be thrown safely.
For example:

Constants and Units:
As this comic is very complicated several screen shots and tables are needed for the full explanation. In order to keep this main page easy to use, these pictures and possibly some of the tables will be placed on some extra pages, as has also been done with other complex comics in the past:
[As this is an interactive comic, not all possible text should be given in this transcript. Also, it is not possible to see all the different throwers or objects in one image. This transcript here includes the text that can be found when loading the page, without changing the thrower or object (the default), but also includes the text that can be found by scrolling in the two select "windows" as that would be similar to a long comic where you need to scroll as well as customization options. For further differences that occur by changing the objects refer to a table of all combinations.]
[A heading with a subheading is above a line, beneath which are a sentence, that is generated by the selections in the two windows beneath this sentence:] Throw Calculator This calculator implements the approximate throwing distance estimation model from How To Chapter 10: How to throw things .
How far could George Washington throw a Microwave oven?
[Beneath this sentence are two "windows" with a frame around them, one to the left and one to the right, each with a heading breaking the top frame. Each also has a scroll bar to the right, which allows one to scroll down through 8 different possible selections in the left window and 16 in the right window. There are, depending on the browser zoom level, one or two selections on each line. Each window's content is given here under their respective headings. Each possible selection is a drawing with a caption beneath it.] Select a thrower
You An NFL Quarterback George Washington Pikachu Carly Rae Jepsen Thor, God of Thunder Chris Hemsworth A squirrel
Select an object to be thrown You A microwave oven A basketball A blender A gold bar A wedding cake A ping-pong ball An acorn Thor's Hammer A javelin George Washington Pikachu A car A silver dollar (spinning) A silver dollar (tumbling) A squirrel
[Below the two windows is the result of the animation that will happen when a selection has been made. An animation of the selected thrower throwing (or failing to throw) the selected object is shown, and the object's traveling distance is measured out both in meters (SI units) and in some other unit in brackets below. If the distance is not too long compared to the size of the object and thrower, then both can be seen, and in case the object is soft it may break from the throw.]
[In the pre-selected version, George Washington throws a microwave oven, which ends up several meters from him lying on a corner broken with its wire lying beneath it. The distance is given under the ruler along which the throw has occurred, with markings for approximately every meter. In this case, there are seven steps even though the distance is above 7 meters:] 7.76 meters (25.46 feet)
[Clicking on "You" in the thrower box opens a new window over the above described comic parts. some of the comic can still be seen including the thrower and his item, and a new throw occurs every time something is changed in this new window. It is a customization box with several options shown below.]
Your Name ____You_____ [can be changed]
Height 5.8 ft [number can be changed; ft can be changed to m]
Mass 160 lb [number can be changed; lb can be changed to kg]
Athleticism [Below is a scale showing Black Hat, Knit Cap depicting You , George Washington, and a person with goggles and a helmet. A marker is set at You, but can be changed. Below the characters are descriptions.] Black Hat: Moving objects around is for suckers. Minimal You: I'm in decent shape and have pretty good form. Decent George Washington: I'm so good at throwing they made me president. Extremely High Goggles: I use a time machine to train for 36 hours a day. Champion Athlete
[Once done the box can be clicking on a cross at the top right or just clicking outside the window on the comic behind it. Now the thrower you (and the object you) will have the weight, length and strength chosen and will be able to throw (or be thrown) with these stats. ]


Cryptic Wifi Networks

Explanation:
In the comic, Knit Cap is on top of a high mountain in a remote location (second comic in a row with knit cap). Mobile devices frequently launch a popup telling users to choose a network to connect to. Knit Cap sees a WiFi network name listed on a handheld device, perhaps a cell phone. This is something you would expect in a city, but certainly not on a mountain top, hence the joke, that what produced these WiFi networks are unknown, but seem to be distributed randomly over the face of the Earth, disregarding nearness to technology.
Cryptic Wi-Fi (or WiFi) network names, called Service Set Identifiers (SSIDs) are part of the joke about not knowing where the corresponding wireless router is located, suggesting they are unexplained phenomena instead of wireless radio devices. Some of the earliest WiFi devices like printers and internet routers advertised cryptic SSIDs, as do many of them today. In 1998, Lucent introduced the WaveLAN IEEE , the first integrated circuit chip set supporting the IEEE 802.11 wireless LAN protocol, spinning off Agere Systems to produce them in 2000. WiFi followed mid-1990s short-range wireless networks like Bluetooth and radio internet protocols like the 1980s KA9Q , with roots going back to the earliest ticker tape digital telegraphy systems from the mid-1850s. Humorous SSID names are not uncommon.
The SSID displayed is Toshiba-U2187-OfficeLink-Net46UHZ which is 33 characters long, unfortunately one character more than are allowed. Toshiba is a multinational electronics conglomerate manufacturing many products including untold multitudes of different kinds of printers over the years. Such devices often have embedded wireless access points including the manufacturer name in the SSID. Many network names contain words like Net, Office or Link. The code might indicate a model U2187 device from Toshiba named (or having an interface program named) OfficeLink, which has a sub-model number or operates on a wireless network designated 46UHZ. That "Hz" is an abbreviation for Hertz suggests that designation may or may not have something to do with the frequency on which the transmitting device operates. 48 microhertz corresponds to a period of 4.1 per day, or a radio wavelength 41 times as far as the Earth is from the Sun. Or U2187 could be the Unicode character code for the Roman numeral 50,000 spelled "ↇ" or a serial number for a user or a utility pole. We don't know whether the SSID is connected to a network of more than one or is just one device. The padlock icon indicates that a password is required to communicate. The "join other network" option allows for manually typing SSIDs to attempt to connect with networks which are not configured to display their SSIDs.
While the most likely explanation in an office environment might be a printer plugged in somewhere nearby, other possibilities include a marsupial delivery drone, television, cryptocurrency mining rig, speaker, pacemaker, alarm system, offshore flying wind turbine, fashion accessory, autonomous antimissile defense system node, hobby project, surveillance device, balloon , distributed denial of service attack platform malware-infested coffee pot, satellite , vending machine, seawater dialysis station, telecommunication facility, solar-powered drone , distributed exoskeleton, visiting interstellar colony(?) ship, power-to-gas pipeline valve, ransomware worm nest, or anything else in the Wifi Internet of Things . Sometimes, the ionosphere reflects radio waves, vastly increasing the distance that they can travel to and from remote locations, but this skywave propagation normally affects frequencies below 30 MHz, and never above 300 MHz, so they couldn't be the cause of receiving far away Wifi signals, which are 900 MHz and above.
Network names can be used to track the geographic locations of mobile devices, for example in the Wi-Fi positioning system . Google street view equipment records locations of networks to assist with geolocation . Location information can be searched in tools like Wigle or OpenWifiMap . The Institute of Electrical and Electronics Engineers (IEEE) committee number for WiFi is 802.11, which is composed of sub-committees like 802.11ad , designing the 60 GHz Multiple Gigabit Wireless System (MGWS) and 802.11ay working on multiple input, multiple output (MIMO) bandwidth enhancements. This portable Toshiba printer supports the "802.11 a/b/g/n" WiFi protocols. The software which produces SSID listings is administered by network communities and depends on mesh configurations . (Please see also 1785: Wifi .) Alternatives include bluetooth mesh networks and other ad hoc networks to provide internet connectivity services.
The title text indicates that the first WiFi networking client interface displayed unexpected SSIDs. If true, this could potentially rule out all of the alternative explanations other than an alien visitation, a software bug, rogue industrial espionage, time travel, trans-multiverse or trans-dimensional communication, hardware misconfiguration, the simulation hypothesis , or the supernatural. (It is worth noting that cryptic-sounding WiFi networks generated by a time-traveling alien entity as a trap was used as a plot device in the 2013 Doctor Who episode " The Bells of Saint John .")

[Knit Cap (who has a backpack) is checking a phone at the highest mountain in a mountainous landscape, with 5 snow covered mountain peaks behind, and a smaller peak connected to and just below that one. There seems to be no snow on those two peaks. Above is a view of the phone's screen as indicated with a zigzag line from the phone's screen to the frame with text. There is also a wifi icon at the top left and a padlock icon at the end of the second line of text. The bottom line is a gray font.] Phone: Available WiFi Networks Phone: Toshiba-U2187-OfficeLink-Net46UHZ Phone: Join other network
[Caption below the panel:] Tech Trivia: No one actually knows what devices produce those cryptic WiFi networks. They just appear at random across the Earth's surface.


Unreachable State

Explanation:
When writing a computer program, developers often need to make assumptions about what state the system could potentially be in at the time the program is executed. For example, a program designed to fetch data from a database requires that the database be accessible at the time it tries to fetch data; if it is not, then the program needs to know how to handle that state, or it might simply hang or crash the system. A good developer will have accounted for this possibility and may give the program a way to fail gracefully; often, this is done by outputting an error message to the user, to tell them what is wrong.
Sometimes, cautious developers will identify states that, in theory, should never be reachable at all - if they were, it would imply that something has gone fundamentally wrong. A paranoid developer might still decide to handle this case anyway, perhaps including a note that the situation should theoretically never happen, but they aren't confident enough to state with absolute certainty that it cannot.
This comic shows Cueball reading (or possibly writing) just such an error message from a program he is using. The developer has evidently written this text while tired (possibly from overwork), and did not trust themself enough to be sure that the state is truly unreachable. The hopeless tone of the message supports this lack of confidence in their work.
The title text refers to the common trope of a character being given a "magic" item and winning something because of it, then being told that the item was not actually magic and that the magic was inside them all along . It is often used as a fable to tell people to follow their dreams. The title text puts the fable in a place where it doesn't belong, saying that finding the "unreachable state" that is the error code implies that the finder can do anything.
[Cueball, sitting on an office chair at his desk with his hands over his laptop computer. There is an error message on the screen which is displayed above him with a zigzag line from the screen to the text. The exclamation mark at the top is shown in white on a black triangle.] ! Error If you're seeing this, the code is in what I thought was an unreachable state. I could give you advice for what to do. But honestly, why should you trust me? I clearly screwed this up. I'm writing a message that should never appear, yet I know it will probably appear someday. On a deep level, I know I'm not up to this task. I'm so sorry.
[Caption below the panel:] Never write error messages tired.


Foucault Pendulum

Explanation:
Black Hat is attending what appears to be a guided tour of a museum with a Foucault pendulum . Megan is explaining to him, Cueball and Ponytail about the device which demonstrates the rotation of the Earth.
Black Hat, being himself, immediately sees an opportunity to cause chaos and seizes it with both hands, quite literally — he grabs the pendulum, which causes the others to shout after him to stop. At first this would seemingly be for fear of ruining the delicate demonstration. However, in the final panel, the news anchor Blondie reveals to us that by arresting the motion of the pendulum, Black Hat has somehow stopped the rotation of the Earth. However, it was only briefly, since the local geophysicists managed to wrestle him down, and it must be assumed that they then quickly restarted the pendulum and thus the Earth's rotation.
This of course is blatantly impossible, since the Foucault pendulum's motion is tied to the Earth's rotation, not the other way around (at least in any significant way, see below). A Foucault pendulum is a regular pendulum that swings from a bearing that allows rotation in any direction, like your shoulder joint instead of your elbow, as a demonstration that the Earth is rotating beneath it. If the Earth were stationary, the pendulum's plane of oscillation would not change relative to its immediate surroundings, but the Earth is not stationary, so the pendulum's plane of oscillation will appear to rotate over the course of a day, although in reality it is the Earth that rotates. The low-friction bearing doesn't allow the rotation of the Earth to affect the motion of the pendulum, so it tends to stay aligned with its original inertial reference frame rather than with its surroundings, which rotate with the Earth. A Foucault pendulum located at one of the poles will take a full day to "move" one full round. At the equator there is no movement, and in between it will take longer than 24 hours (24 hours divided by the sine of the latitude).
The fact that the Earth's rotation does not influence the motion of the pendulum does NOT mean that other forces can't affect it - for example, someone running up and manually repositioning the pendulum. Of course, the apparent rotation of the pendulum's plane relative to the Earth is an effect of the planet's motion, rather than the cause of it. Thus, stopping a Foucault pendulum manually does not entail pausing the rotation of the Earth. [ citation needed ]
If it were somehow possible for a Foucault pendulum to control Earth's rotation (see above), Black Hat would probably not want to alter the momentum of the pendulum if he were not at one of the Earth's poles. That is assuming he was told that it was related to Earth's rotation and assuming that he would prefer to preserve his own life over creating chaos (unless he has some means to prevent his being slammed into a nearby wall at the speed of sound). This is because, if the rotation of the Earth were to be stopped for even very short amounts of time (a few seconds), it would cause everything on Earth that wasn't bolted/fastened to the ground to move eastward compared to the now stationary ground. Objects near the Equator would suddenly be moving at a speed of 300-360 meters per second, likely causing the death of most lifeforms on Earth beneath a certain latitude almost instantaneously. Those close enough to the poles may survive, though. Also this will cause massive windstorms, tsunamis, volcanic and tectonic events on a scale not previously observed on Earth. This would likely cause a mass extinction event and wipe out most of humanity in the initial events (which would eventually lead to our total extinction). It is possible that Black Hat's grabbing the pendulum would cause a gradual slowing prior to stopping, minimizing the issue (though this doesn't seem to be the case), but the results would still be catastrophic, as the aforementioned events are still likely to occur (specifically the tsunamis and volcanic events). However, as mentioned above, if this pendulum were located at the South Pole, then Black Hat and other people around him would not be affected immediately, and he could both do it, survive and be stopped again. The question is whether there would be any more news stories to cover this, given what would happen to the rest of the world! If there was no one to readjust the pendulum's rotation, then certain events would happen after the initial damage (see this video [1] ). Randall previously covered this scenario in detail in his what if? book, see XKCD's Creator Explains What Would Happen If Earth Stopped Spinning .
To be completely correct, the angular momentum of the Earth+pendulum system is constant, so that when Black Hat "stops" the pendulum's rotation with respect to the Earth, he actually transfers to the pendulum some of Earth's angular momentum, thereby slightly slowing Earth's rotation. But the order of magnitude of that effect is (at most) in proportion to the pendulum-to-Earth mass ratio. Earth's mass being ~6 x 10 24 kg, the effect for any practical pendulum would be beyond the 20th decimal place and would therefore go totally unnoticed.
The title text mentions the International Earth Rotation and Reference Systems Service , an organization providing standards for global time and reference frames; this organization would have a very rough day after the fiasco with Black Hat. The title text refers to a (probably) fictional paramilitary enforcement arm of this organization and the foolishness of tangling with such a force. If Foucault pendulums were somehow able to influence the rotation of the Earth in any measurable way, the IERS enforcers would probably strictly control their installation and monitor their use (and misuse). Black Hat is likely in for a rough day as well. It seems likely that some on this team are geophysicists, since they were the ones who took Black Hat down.
[Megan is addressing Cueball, Black Hat and Ponytail as they are looking a pendulum, which consists of a large swinging sphere with a spike beneath it hanging on a string coming down from above with seven small markers under it. Megan is pointing at it while it is swinging towards them, as indicated with lines behind the sphere and the string.] Megan: This Foucault pendulum demonstrates Earth's rotation. It stays in a fixed plane while the Earth rotates under it.
[Close-up on Black Hat holding a hand to his chin.] Black Hat: Hmm, really. Black Hat: So that means...
[Zoom out to Black Hat running to the pendulum grabbing it with both hands. He knocks over two of the seven markers that can now be seen to be small pegs standing up on he floor beneath the pendulum. A line goes from his hand on the pendulum up to a sound bubble. Two people off-panel yell at him.] Character off-panel 1: Hey! Character off-panel 2: Stop him! Sound: Grab!
[Blondie as a news anchor uses her held out hand to indicate Black Hat who is shown on a screen next to her. There is a caption in two lines above it. The first line in normal text, the second line in white in a black rectangle. There are further unreadable text below the picture.] Blondie: The Earth's rotation was briefly halted today until geophysicists wrestled the intruder to the ground... Breaking news


Earth-Like Exoplanet

Explanation:
This comic is a reference to the recent discovery of water vapor in the atmosphere of exoplanet K2-18b . The planet was discovered already in 2015 by the Kepler Space Observatory , orbiting the red dwarf star K2-18 . Water on exoplanets is considered a biosignature , meaning it's an indicator that there could be life there. However, as Megan reveals the planet's other characteristics, it becomes clear that it is unlikely to actually support life, and in fact is actually a horrible hellscape. The question of habitability by higher forms of life is profoundly different from the way astrobiologists use the term for microbes. Even a "survivable zone" can't mitigate the description of just how inhospitable this new wet planet would be to life as we know it, save possibly for extremophile organisms. In the comic 1231: Habitable Zone , this zone was the subject.
The planet being tidally locked indicates that the same side would face the planet's star year-round, meaning half of the planet would be in constant day and the other half would be in constant night. It is believed that K2-18b is tidally locked . Based on our (admittedly limited) understanding of life, abiogenesis can only occur in environments with liquid water; however, the day hemisphere would likely be so hot that all water found there would be in a gaseous state, and all water found in the night hemisphere would likely be frozen due to the intense cold. If life were to be found on this exoplanet, it would be in the twilight strip, a thin ring around the edge separating the two hemispheres where sunlight can reach but is refracted by the atmosphere. The environment in the twilight strip would thus experience something akin to an eternal sunset, and temperatures there would be moderate enough to allow life to come about.
Unfortunately, the other characteristics of the exoplanet severely undermine our chances of finding life even in its twilight strip, as there are many problems with the habitability of red dwarf systems .
The comic uses swinging blades as a metaphor to succinctly describe the planet's perilous conditions. That is, as far we know, there are no actual swinging blades on K2-18b. [ citation needed ] Swinging blades made their first famous appearance in the Edgar Allan Poe poem "The Pit and the Pendulum ," where the titular pendulum was a large blade swinging back and forth slowly. Due to the fame of Poe's work and the number of allusions made to it over the years, swinging blades have become a common feature in fictional deathtraps, and were used as an analogy to illustrate that the planet is chronically inhospitable to life.
"Biosignatures in the form of screaming" suggests that any life that had developed on the planet would be in continuous pain or fear due to their hazardous surroundings. In addition, this suggests that the screaming of these organisms would cause ripples in the atmosphere which we should be able to detect light-years away through the vacuum of space and that it would be more noticeable than other signs of life (such as the spectra from the ash produced by burning organic material.)
The title text mentions that fire could indicate the presence of life. This is because fire requires both fuel and oxygen (or some other similar, reactive gas). The occurrence of fire suggests that those things are both being continuously produced by some process.  The most likely processes we know for producing oxygen are biological.  The irony, of course, is that fire is also very dangerous, and almost universally lethal to organisms that are exposed to it for long enough. Munroe points out that oxygen reliably indicates that there was life, before the fire, with the implication that the fire may have killed everything.
[Side view of Megan standing behind a lectern, speaking to an off-panel audience in front of her. Two people from the audience react to her statement.] Megan: We've discovered the most earth-like exoplanet yet! Off-panel voices: Yay!!
[Front view of Megan behind lectern:] Megan: Well, it's in the habitable zone. Habitable-ish. "Habitable." Megan: The survivable zone.
[In a frameless panel with the same setting as before, Megan holds her left hand out with palm up.] Megan: It's tidally locked. And blasted with stellar flares. And probably meteors. And bathed in acid.
[Closeup side view of Megan, now holding up a finger on her left hand. Again an unseen audience member replies.] Megan: But we've detected water vapor! In between all the swinging blades. Off-panel voice: I see. Megan: We're hoping to find biosignatures in the form of screaming.


Prescience

Explanation:
In this comic, Cueball states that it's been a long time since there's been a really big meteor impact . Due to the Gambler's Fallacy , this is taken to be Cueball implying that a big meteor impact is coming soon. The off-panel voice is annoyed about his statement, but whether from fear of it happening or because he does this all the time is unclear, see more below. The joke is that Cueball does this often, also with other types of major random events, just in case they do actually happen soon. For instance, if there does happen to be an impact soon after he made the statement, it makes him look incredibly prescient , whereas if there isn't one, no one really cares or remembers.
It is also unclear how big an impact he refers to. It has been 60 million years since the impact that killed the dinosaurs , but that if that is the type of event he refers to, then maybe no one will be there to remember what he said. So it is likely much smaller impacts he is talking about.
Prescience means to predict the future. It is clear from this comic that Randall makes fun of both of those that claim to have prescience and of those that have a superstition against talking about something happening that could cause it to happen.
Although only one method is scientifically recognized, there are at least three possible sources of prescience recognized by people.
The first of the two main ways of predicting the future involves a mix of common sense and historical knowledge.  By understanding the past, the direction of the future can be guessed at with varying levels of accuracy.  This type of prescience is also known sometimes as future modeling, statistical prediction, and even wisdom to name a few.
The second way to predict the future is not scientifically recognized but remains popular in culture and fiction.  It can involve magic, psychic power, higher powers (gods), and other such methods.  Collectively, they are labeled supernatural; any method to predict the future using this class of method cannot be easily measured by science.
Although not technically a way to predict the future, the third way to predict the future is through superstition.  The method involved in this comic effectively boils down to "speak the name of evil, and you will summon it."  This superstition can have surprising power in people's lives, however.  A woman planning her outdoor wedding may feel the urge to hit her friend if they say "Gosh, I hope it doesn't rain on that day."  A doctor working in the Emergency Room may feel the need to kick anyone who says "Wow, it's really quiet around here."  Such thoughts spoken aloud do not have the power to control the weather or cause people to seriously injure themselves.  Yet people often react emotionally as if not speaking the name of 'evil' will keep it away.
This comic may reflect that emotional reaction when the off-screen character yells at Cueball: "Will you stop that?!". Alternatively, it is one, like Megan , who knows Cueball well enough to know that which is stated in the caption, that he only does this to look good if said thing happens. And the person is so tired of it! Maybe Cueball does it at least once a week, and obviously from the caption, it is not only about meteor impact, but any major random event, that he could then be remembered as having predicted.
The title, Prescience, has a double meaning. The first meaning is about the prescience that would appear if one actually predicts a natural disaster this way. The second meaning involves the fact that it is spelled pre-science - since there are many more scientific ways to predict meteor impacts, even though they aren't entirely accurate.
The title text refers to the RMS Titanic , a ship which was claimed to be unsinkable by those promoting its maiden voyage. But then it struck an iceberg in an unfortunate way so more compartments would be filled with water that it could survive; and, therefore, it could and eventually would sink. But with all the news stories that had just been published hailing this unsinkable ship as a modern wonder of the world, this shipwreck was particularly ironic. The story of the sinking of the Titanic has been memorialized in popular culture, most memorably in the 1997 film Titanic .
In the title text, Randall thus suggests that lots of ships had been called unsinkable before Titanic. But saying such hubris out loud doesn't make any ship more likely to sink. But when such a ship, like Titanic, then sinks it does, however, increase the value of the story ensuring it will be remembered.
It should be noted that few among the ship's builders or crew boasted the Titanic to be unsinkable. Most of the boasting came from the owners that used the news media of the day to create hype and promote their ship, just when the ship was finished and dedicated (the ship's builders did, however, boast that the ship exceeded all safety standards of the time). In addition, the hubris was only one small part of the fame of the sinking of the Titanic ; the Titanic' s status as a world record setter for most massive ship ever built, the incredible wealth of most of its passengers, and the fact it sank on its maiden voyage all contributed to the fame and hype behind the great maritime tragedy.
Ironically part of what caused this disaster was hubris, since those that were interested in promoting the ship also wished it to make a speed record, by reaching New York a day before expected. Thus the captain, even though he would have realised that the ship could sink, took the fateful decisions of running at full speed through waters known to contain icebergs during a still night with very calm waters. Spotting icebergs in such conditions is known to be difficult, especially as there will be no notably foaming waves around the icebergs' bases and patchy mists will inconveniently diffuse the horizons and any useful starlight.
[Cueball is sitting in an armchair holding a book. He seems to be looking off as he talks to an off-panel person behind him. This person replies.] Cueball: You know, it's been a while since there's been a really big meteor impact. Off-panel voice: Will you stop that?!
[Caption below the panel:] I say this kind of thing every so often, because I don't believe it affects the outcome and it has a slim chance of looking incredibly prescient.


Ksp 2

Explanation:
Cueball , a programmer, is sitting at his computer while four other persons from NASA , Hairy , Ponytail , Hairbun and another Cueball-like person try to convince him to delay the release of a sequel to Kerbal Space Program (KSP 2).
Kerbal Space Program (KSP for short) is a space flight simulation video game with a Keplerian orbital physics engine, allowing for semi-realistic orbital maneuvers. KSP is a recurring theme in xkcd. A sequel, abbreviated here as KSP 2, was planned at the time of the comic's publication to be released in 2020, although it has since been delayed to Early 2023.
Also planned for 2020 is the Perseverance mission, a mars rover originally named Mars 2020 , which successfully landed. The joke in the comic comes as engineers are likely to want to extensively play with KSP 2 to the exclusion of other things, and NASA is worried about the Mars 2020 mission being delayed or failing because the engineers are too focused on playing KSP 2, including taking an extended vacation and "sick" days off.
Cueball, sitting at a desk in front of a computer, is represented here as being in charge of KSP 2, and the other characters standing around him are pleading with him to delay the release of KSP 2 until the Mars rover program is complete, even being willing to "give [him] a moon".
Offering to give somebody the moon occurs occasionally in songs and poetry, as an idiom meaning desire to offer something of great value, or expressing great desire to please.  Literally giving a moon to Cueball is impossible, [ citation needed ] but it is possible to name a moon after Cueball, so that may be what is implied instead.  This could also be a reference to the film Despicable Me , which revolves around Gru and his Minions trying to steal the Moon.  The Kerbals (mascots of Kerbal Space Program) resemble the Minions from the film.
The title text is a sentence said by someone from a committee in NASA that oversees the progress and budget of the Mars 2020 mission. They are satisfied that the launch in 2020 is still on track, but has a question regarding the 'human capital/personnel retention' budget, which has several unmarked cash payments, more than they would expect. As they begin to ask what they are, someone from the Mars 2020 project interrupts, having probably foreseen this question, stating that it is Public outreach.
In the original Kerbal Space Program, playing in career mode, the player can select various "strategies" at the administration building to exchange or boost various assets.  "Public Outreach" appears similar to the "Public Relations" strategy "Appreciation Campaign", which exchanges a portion of in-game money earned completing mission contracts for prestige, which has an effect on mission contracts the game makes available.
The title text suggests NASA could be paying Private Division, the developers of Kerbal Space Program, money to delay their release until after the Mars mission.
NASA has dabbled in game physics engines for "public outreach," with the same mixed record of success as any promising R&D endeavor. Pertinent projects included a series of collaboration laboratories on various forms of social media including Second Life which hosted a "NASA CoLab" region active from 2007 to around 2013. While the unrealistic constraints imposed by real-time physics engine simulation prevented much actual engineering, such shared 3D computer aided design (CAD) systems provide a measure of drafting training in a play sandbox system outside of a formal work environment. NASA frequently holds design competitions, including some in which winning participants have spoken highly of KSP, and some of which are used for developments in medical informatics, for example, outside the field of aerospace engineering and space colonization simulation. The use of game development competitions to assist scientific progress is also used in the Fold.it competitive protein folding game, where the winners build antibodies to save the lives of those who have health care. Such efforts have often been supported by SBIR -sized government agency grants from several countries, along with other individuals (i.e., customer) support and help from organizations to build software improving competitive score achievement. NASA has also been involved in asking software publishers to remove, withdraw, or restrict their releases, such as the COMSOL plasma physics engine library, rumored to be useful for the design of nuclear weapons. But whether any government agency has ever paid for the delay of a computer simulation game in order to increase their productivity is an open question.
An alternative suggestion of the title text is that NASA gave cash to employees, their families, friends, associates, and foreign spy followers to purchase additional copies of KSP 2 to encourage development innovations, international collaboration, as a "force multiplier" for personnel retention, and as bonus incentive awards for engineers who are ahead of schedule for their part of the Mars 2020 launch.
[Cueball is sitting in an office chair at his desk in front of a computer. He is surrounded by four people, and is looking over his shoulder at the ones standing behind him, Hairy - holding his palms up - and Ponytail stretching her arms out towards him. On the other side of the desk is another Cueball-like guy holding his arms out palms up and Hairbun who stretches her arms out to the side.] Hairy: Please hold off until the end of summer. We can't afford the personnel hit right before the late July launch window. Ponytail: People have already started calling in sick! Hairbun: Do you want a moon? We'll give you a moon!
[Caption below the panel:] NASA tries desperately to get the Kerbal Space Program team to delay KSP 2 until after the Mars 2020 mission launches.


Types of Approximation

Explanation:
In physics and engineering, problem solving typically requires approximations , as physical properties of the universe can be difficult to model. For example, in introductory physics classes, theories are introduced in frictionless environments. The level of precision required in a calculation or approximation varies depending on the context.
In the comic, Cueball , the physicist, generally dealing with theoretical constructs that can use relatively simple math, is introducing a problem with the assumption that the particular curve is a (perfectly) circular arc with a radius represented by R. Engineers have to deal with real things, which deviate from ideal shapes. Dimensions may be known to a certain tolerance. Megan , the engineer, also assumes that the curve is similar to a circle, with a deviation factor of 1/1000 or less.
The joke arises when Ponytail , the cosmologist, uses the much less precise approximation of pi (π) equal to 1.
Ponytail offering to use 10 instead of 1 alludes to Fermi approximations , as shown in Paint the Earth . Numbers are rounded to the nearest order of magnitude (1, 10, 100, etc.) using a base 10 logarithmic scale. On this scale, "halfway" between 1 and 10 would be √ 10 ≈ 3.16. Thus, numbers between about 0.316 and 3.16 are rounded to 1, between 3.16 and 31.6 are rounded to 10, and so on. Pi is an irrational number that can be approximated by 3.14, so it is very close to the 3.16 cutoff point. The closest order of magnitude to pi is 10 0 , or 1. But using this form of estimation it doesn't really matter to Ponytail whether pi is approximated to 1 or the other reasonable Fermi approximation, 10 1 , or 10.
Pi is defined as the ratio of the circumference of a circle divided by its diameter. This number is an irrational starting with 3.14159, the value for this ratio in a flat geometry. But in a curved space , the ratio might be different. The title text makes use of the fact that almost every number can be this ratio depending on the curvature of the space the circle is in. The cosmologist doesn't know the curvature of "this particular universe" (a funny way to state the universe the cosmologist lives in, which is not perfectly flat ), and so pi may not be the best value to use for the ratio between a circle's circumference and diameter.
This comic is a parody of the tendency of cosmology to use much rougher approximations in their work that would horrify engineers, other physicists, mathematicians, etc. In general, cosmologists deal with distances, time spans, masses, etc. that are so vast, with such large estimated errors, that approximations that would be ridiculous elsewhere still yield useful answers in cosmology. When dealing with the large numbers in cosmology, small multiplicative factors like 3 vanish into the rounding error: there probably isn't a useful difference between 10 100 and 10 100.497 , even though these numbers differ by a factor very close to pi -- an error that would greatly disturb most physicists and engineers.
Approximating pi as 1 may also refer to the habit astronomers have of changing the units of measure such that important constants of the universe (such as the speed of light or the gravitational constant) are equal to 1, which highly simplifies the formulas without compromising the math. The number pi, however, is a dimensionless ratio, which doesn't depend on the unit of measure.
[Three panels show the same setup with three different characters. In the upper-right corner of each panel is the lower-left portion of a wheel and hub diagram, showing two spokes going out to a curved rail. The two spokes connect to the rail with a small raised portion on the inside of the rail. There are both readable and unreadable text/symbols both outside and inside the curve and an equation below the curved rail. There are two small squares with readable labels. The three different characters are all holding a pointer up to the diagram while explaining an assumption. In the last panel an off-panel voice interrupts the speaker. This means the text from the reply to this comment goes further down over the diagram, so the top is hidden by text, compared to the first two. Above each panel is a label with the character's profession. As the text on the diagram is the same on all three panel, this text is shown here:] r 1 r 2 d=2π(r 1 +r 2 )/2
[Panel 1 - Cueball. Caption above:] Physicist Approximations Cueball: We'll assume the curve of this rail is a circular arc with radius R .
[Panel 2 - Megan. Caption above:] Engineer Approximations Megan: Let's assume this curve deviates from a circle by no more than 1 part in 1,000.
[Panel 3 - Ponytail. Caption above:] Cosmologist Approximations Ponytail: Assume pi is one. Off-panel voice: Pretty sure it's bigger than that. Ponytail: OK, we can make it ten. Whatever.


Mavis Beacon

Explanation:
Cueball is being congratulated by the game he plays, Mavis Beacon , on his computer, because he has beaten the end boss and unlocked a new ability - the ability to type capital numbers...
Mavis Beacon Teaches Typing is a computer game first released in 1987, with the goal of teaching touch-typing and improving typing speed on a computer keyboard. Unlike many video games, Mavis Beacon contains no combat and therefore does not feature any " end boss " (a very powerful enemy encountered as the final challenge of the game). In many video games, defeating major opponents "unlocks" special features, such as improved weapons. Also, playing Mavis Beacon , although it may improve typing skill, has no effect on how typing works on one's computer.
In the caption, however, Randall asserts that after 30 years of playing Mavis Beacon , he encountered and defeated such a boss. Playing the same game for 30 years is rare [ citation needed ] . Regardless, Randall claims that defeating this "end boss" unlocked an ability to type esoteric "capital numbers," which Randall depicts as more extravagant versions of the familiar numerals. Although modern Latin letters have different letter case (i.e. capital or upper case  and small or lower-case), Arabic numerals - the conventional numerals 0-9 used in the Western world - do not.
Stating that the game is old enough that it could have been played for 30 years, could be another attempt at making people, who actually did play the game in the early days, feel old (or an appeal to nostalgia). But this doesn't seem to be the main point of the comic.
Typing such numerals is said to require pressing the Alt, tilde (~), Scroll Lock, and numeral keys at the same time. Some keyboard layouts do not have a scroll lock key or a separate tilde key (such that pressing ~ actually requires pressing a shift/ modifier key along with the ~ key), and in any event pressing four or five keys at once would be quite difficult. Needless to say, pressing all those keys simultaneously does not, in fact, do anything like what the comics describes in any known computer system, though some smaller subset of those keys together (i.e. "Alt ~" or "Alt numeral-key") might activate other operating system or user-defined shortcuts.
Keyboards vary in how many simultaneous key presses they can process ( rollover ).  Computer keyboards for English may be limited to as few as 3 simultaneous keys, whereas other languages or higher quality keyboards may be able to handle an unlimited number of keys at once.  (A musical keyboard might need to handle 10 or more simultaneous keys, likewise gaming or braille keyboards may need to handle many simultaneous keys.)
In the title text, Randall notes that certain typefaces feature text figures , numerals that have ascenders and descenders, much as lower-case letters do, rather than all standing at the full X-height like capital letters. He then goes on to joke that, conversely, there are true "capital numerals," but they are a guarded secret of Mavis Beacon. Mavis Beacon was the character created as the typing instructor for the Mavis Beacon game, and is fictional, not a real person. Additionally, as a typing instructor, this person (even if she actually existed) would not be able to change typographical standards. Randall's description of Mavis Beacon as a "number maven " (that is, expert or connoisseur) contrasts with her supposed field of expertise in typing, which involves letters and punctuation more than numbers.
The comic itself hotlinks to this article: Oldstyle Figures . It is about typographic oldstyle digits.  The article assert that oldstyle digits are also called "lowercase" digits.
[Cueball is sitting in an office chair at his desk in front of his computer reading a message that is shown coming from the screen with a zigzag line, going to the text above him. The two upper lines (of five) are separated from the lines below, but connected with a small zigzag line. The computer short cut is written in three boxes. The last line is the numbers from 1 to 9 and 0, in a highly stylized format but recognizable in this context. The digits are shown below in their standard appearance since the stylized versions cannot be reproduced in this transcript.] Congratulations. Use this power wisely.
Key Code (secret!!): Alt + Tilde + Scroll Lock + Number 1234567890
[Caption below the panel:] After 30 years, I finally beat the end boss of Mavis Beacon and unlocked the ability to type capital numbers.


Math Work

Explanation:
White Hat is observing a physicist , Cueball , who is staring at some equations and diagrams on a chalkboard (unreadable in the comic). White Hat is neither a physicist nor a mathematician , but he seems to glorify those professions. He wishes he understood the mathematics in Cueball's work and "the beauty on display here." People who profess a love for mathematics often cite the beauty they see in pure math, how things work out so perfectly, as the reason they love math.
The joke here is that Cueball as a physicist is doing something instead quite simple and relatable: Avoiding hard work. Solving many kinds of constraints for two unknowns isn't necessarily difficult, but can be depending on the details. Cueball clearly thinks a solution is possible but would rather find an easier route. The same could be said about the field of mathematics in general: A proof is beautiful to a mathematician when it provides aesthetic pleasure, usually associated with being easy to understand. A proof is elegant when it is both easy to understand and correct, and mathematical solutions are profound when useful.
The title text continues Cueball's thought process, with the possibility of using an automatic equation solver to find the unknowns. Equation solvers are not often considered beautiful ways to address purely mathematical problems, even if they are often the most efficient and in that sense elegant solutions to applied problems in engineering. Using a formal solver with symbolic, numeric, or both methods requires making sure that the constraints (e.g. equations) are entered correctly, with parentheses balanced in their correct locations for the solution to succeed. This might be a further joke about Cueball's laziness, suggesting that he doesn't even have the energy to check whether his parentheses are placed correctly. At the same time it might show how far away he is from finding the real solution: Any missing, misplaced or spurious parenthesis will most likely immediately invalidate the whole equation system.
[White Hat is watching Cueball from a couple of meters away. Cueball is contemplating the formulas and diagrams that fills the blackboard he stands in front of. Cueball holds a chalk in his hand. None of the content on the blackboard is readable, but there is a diagram in the shape of a circle and a another pie shaped diagram. Both are thinking with large thought bubbles above their heads, with small bubbles connecting them and the larger bubble.] White Hat (thinking): Amazing watching a physicist at work, exploring universes in a symphony of numbers. White Hat (thinking): If only I had studied math, I could appreciate the beauty on display here.
Cueball (thinking): Oh no. This has two unknowns. That's gonna be really hard. Cueball (thinking): Ughhhhhhh. Cueball (thinking): Think. There's gotta be a way to avoid doing all that work...


Drone Fishing

Explanation:
Another comic in the My Hobby series.
This comic is a parody of the traditional activity of fishing for fish. Typically, a person who is fishing will sit as Cueball does in this comic, by some body of water and wait for a fish to bite their cast line. However, some fisherman will use a kite to allow them to cast their line further in the water, and this is called " Kite fishing ". But it is also possible to use drones for this, as in "drone fishing."
Randall , however, is interpreting "Drone fishing" not as fishing with drones but as fishing for drones ("drone fishing" as in "lobster fishing"). In fact, what Cueball (or Randall) is doing, is kite fishing for drones, by flying a kite with fishhooks attached over some drone enthusiasts in hopes of snagging their drones. This is quite likely illegal, especially if Cueball were to "reel" the caught drone in. [ citation needed ] It seems like he has already caught two that lay in front of his feet. All the drones are of the quadcopter type, as they are called in 1630: Quadcopter .
The title text parodies a common line about fishing, about the "joy of going out in nature", catching fish, and the struggle of reeling in large fish. However, instead of being about fishing, Randall has replaced the line to be about catching drones, and fighting off their owners. Considering that the two drone owners beneath his kite are children, Science Girl and a Cueball like kid, clearly smaller than Cueball/Randall in the chair, this should not be so tough in the pictured case.
Real life methods for capturing drones involve French Army falconry training of golden eagles (a technique abandoned by Dutch police) and firing nets from other drones, which has been proposed for orbital debris removal , or the use of nets hanging on counter-drones.
A similar setup for catching bats with hooks on a kite string have been used, although it's illegal. It seems unlikely that Randall has had this in mind when he made this comic though.
[Cueball is seated in a leaning chair, with a tackle box behind it and two drones lying on the ground in front of him. He is holding a fishing rod from which he is flying a kite on a long string. The kite is high up in the air and far away from Cueball. On the long string there are three smaller lines dangling below the string closer to the kite that to Cueball. Each line has six hooks evenly spread out, from a bit beneath the string to the end of the lines. Three quadcopter type drones are in the air nearby, with Science Girl and a Cueball-like kid standing right beneath the kite holding remote-controls for their respective drones. They are facing each other, the Cueball-like kid looking up, whereas Science Girl seems to be looking at the drone right in front of her, between and just above the kids. It has just begun to rise up as shown by lines beneath it. The two other drones are on either side of the kite line, both flying towards the hooks. Whoever controls the third drone must be off panel, and it is not clear which of those two the kid is controlling. The only text is a caption below the panel:] My Hobby: Drone Fishing


Fresh Pears

Explanation:
Here, Beret Guy has set up a machine advertising "fresh pears". Megan , presumably his first customer, has inserted her quarters into the machine for the specified price, and expresses concern that the pears aren't being dispensed; Beret Guy simply assures her that "it takes a while to work".
Behind the front of the machine, thus hidden from Megan, we see that what the machine does is dispense a seed into the dirt via a small cannon. Above it is a robotic arm and a hopper for collecting and dispensing the ripened pears. So it seems that Megan will have to rattle the coin-slot "a while" before she gets her fresh pear.
The term "a while" is ambiguous, but in the context of waiting for a vending machine to dispense food, it's usually assumed to be a matter of seconds [ citation needed ] .  Beret Guy, in his typical surrealist approach to business , seems to consider it reasonable to wait at the machine for years until a tree has sprouted from the dispensed seed, grown to maturity and begun bearing fruit, that could be picked by the robotic arm and dispensed to the buyer. This could easily take between 5-8 years for a pear tree, when starting only with a seed!  While such a pear would indeed be "fresh", it's implausible that anyone would accept that kind of lag time in buying a pear at a vending machine, even if it is cheap, particularly considering that any number of factors could interfere with the production of pears in the meantime. [ citation needed ] Alternatively, Beret Guy may be planning on using time-altering abilities to rapidly grow the tree.
This comic strip may be based on a fable about an old man who plants trees, knowing that he will not be alive when they bear fruit, to "pay it forward" to his children as his ancestors planted the trees that had sprouted and fed him.  Beret Guy may be practicing good moral behavior and ecological stewardship, but as a customer-facing business model it leaves a little to be desired.
It seems Megan is one of the first to use the machine, as no pear sprouts are shown behind the machine.
The title text refers to the increased difficulty in cultivating desirable apples , as compared to other fruits.  Apples cannot be reliably produced from seeds, seedlings often don't survive, and even when they do, they don't generally reflect the characteristics of the parent plant. As a result, apple orchards are created by grafting tissue from desirable trees onto suitable rootstock.  This process is more complex and labor-intensive than simply planting seeds.  The joke, then, is that the next planned version of the machine would not only require the user to wait years, but would also involve as-yet unavailable technology to automatically perform the grafting process as to create an apple tree that produces desirable fruit.
[Megan is rattling the coin-slot of a machine while Beret Guy stands behind her arm held out towards her. The Machine has a tall wall in front of Megan, with only the coin-slot and a dispenser visible to her. Behind it is a hopper connected to the dispenser. On top of that is a two time folded arm with a gripper at the end. Below this is a box with a label. Beneath the box is a small cannon like protrusion, which shoots something into the dirt to the left of the machine. There are lines indicating both the explosion, the trajectory of the projectile and the impact with sounds noted at either end. Behind White Hat is a sign.] Box Label: Seeds Cannon: Ptoo Impact: Thwup Coin-slot: Rattle rattle Megan: I put in my quarters. Is the machine broken? Beret Guy: It just takes a while to work. Sign: Fresh pears 50¢


College Athletes

Explanation:
Ponytail is reading from her phone about the California Fair Pay to Play act , which was signed into law on September 30, 2019, two days before this comic was released. It gives college athletes the rights to their name and image (face, body, etc.) for financial gain, in contrast to NCAA rules which require that athletes be unpaid. This bill threatens the NCAA's notion of amateurism , which has become a topic of public debate.
White Hat thinks this law is a good thing, but then Cueball claims that his state has passed an even better law giving college players rights to the names and images of any California athletes. Note that Cueball's state is thus not California, so it is very odd they can use names from another state, in addition to the oddity of gaining rights to another person's name and image.
Ponytail doesn't believe Cueball, but he carries on claiming that all members of his school's basketball team thus have changed their name to Steph Curry after the NBA player who plays for the Golden State Warriors , a team in California. Cueball explains in particular that only one player copied the name from the NBA player, then another member of the team copied the name from that player, and so on.
As it turns out, in his final remark, all this has only been the setup for his grand joke: Cueball tells Ponytail and White Hat that this process of recursive name usage is known as "currying". In addition to a pun with basketball rules against carrying , avoidance of which often involves passing from one player to another, this is also a play on both the basketball player's name "Curry" used here, as well as the mathematical procedure called currying , named after mathematician Haskell Curry . This sort of humor is very typical of Cueball, leading Ponytail to state that she "hates him".
Currying is when a multi-variable function is broken down into a sequence of single-variable functions, each of which outputs a new function until the final variable is consumed. For example, the function f(x,y,z) can be curried into f(x)(y)(z), where f is a function that consumes x and produces a function f(x), which in turn consumes y, yielding the function f(x)(y), and that in turn is a function f(x)(y) which consumes the parameter z to finally produce f(x)(y)(z), which is equal to the original f(x,y,z). This is not commonly used in most areas of math except for foundational logic but it is widely used in functional programming.
When Cueball says a team made up entirely of Steph Currys , White Hat questions what the plural form should be, and should it instead have been " Stephs Curry "? This is referring to the pluralization of phrases where a noun is followed by a modifier of some sort, such as attorneys general , parts unknown , heirs apparent , mothers-in-law , and so on. In these cases, plurals are formed by pluralizing the noun parts of the phrases; however, some of these are rare or foreign enough that speakers of English don't always identify them correctly and pluralize the last word instead, e.g. attorney generals .
The title text is a computer science joke, saying that the Steph Currys basketball team's signature play is the "three-point combinator", a joke on the three-point play in basketball, and a type of fixed-point combinator called the Y Combinator , introduced by Haskell Curry. The description of "three-point combinator" is dense with word play that relates to the Y Combinator, which is used to implement recursive methods in functional programming languages, has notable properties relating to halting (see: the halting problem ), and has a common form in which a second argument is used as a counter that is increased by one with each recursive call until termination. "Signature play" may also be a play on words, as currying transforms a method signature .
In this case, when this move is performed, it will just keep accumulating points, as it is guaranteed it cannot halt and will not stop until the time runs out and the buzzer that ends the game is activated. Such a move can of course not be a part of a real basketball game, and more of a nod to the Golden State Warriors' reputation as a high-scoring, nearly-unstoppable offense widely known for three-point shooting.
[Cueball, Ponytail and White Hat are having a conversation. Ponytail is checking her phone.] Ponytail: Oh, huh. California passed a law giving college athletes full rights to their names and images. White Hat: Good, I think?
[Cueball holds his hand up in a fist, while Ponytail, holding her phone down, and White Hat looks at him.] Cueball: That's nothing. Our state gave college players rights to use the names and images of any California athletes. Ponytail: It did not.
[In a frame-less panel Cueball holds his hands out, Ponytail's phone is gone and White Hat puts a hand to his chin.] Cueball: Sure it did! Cueball: That's how our school fielded a basketball team made up entirely of Steph Currys. White Hat: Or is the plural "Stephs Curry"?
[Cueball holds both hands up in front of him. Ponytail has her arms down but she is balling her hands into fists.] Cueball: They didn't all copy the original Steph, though. One player got the rights to his name, then the next player got it from them, and so on. Cueball: This process is known as "currying". Ponytail: ...I hate you so much.


Hours Before Departure

Explanation:
This comic, as from the caption, depicts Neil Armstrong , Buzz Aldrin and Michael Collins , leaving in their spacesuits ( Cueballs with helmets) to go in a NASA van at 6:27, to be shot into space on a Saturn V rocket to fly to the Moon on the Apollo 11 mission (1969). The launch happened at 9:32 on July 16, just a bit more than 3 hours after they left for the launch pad.
The joke is that Randall is amazed they manage this in just three hours, given that he himself tends to arrive too early at the airport, and since they typically ask you to be there two hours before an international flight, he probably leaves from home more than three hours before his departure.
Catching transportation from one place to another requires being there and being prepared before the vehicle leaves. Some transportation, such as public city buses and personal cars require very little in preparation, and one can leave as soon as the vehicle is there and ready.  Others have more complications involved, whether it be in payment, security, slower boarding, etc.
To board a Greyhound bus , for example, one would normally need to be there 10-15 minutes before it is scheduled to leave, because it takes time to get everyone on board at the same time, stow luggage, and present a boarding pass or proof of payment.
Boarding an airline flight is even more complicated (security checkpoints, long terminal walks, more bags, etc.) making the delays longer, and so conventional advice is to arrive two hours early for a domestic (same country) flight and three hours for an international flight. Seasoned travelers can often cut these times shorter, but to be ready for unexpectedly long delays the less experienced traveler would want to leave themselves plenty of time.
Based on that, the exceedingly complicated business of traveling to space would instinctively require you to be ready much longer than the three hours they recommend for international flights, however, three hours is about how long it took for the astronauts traveling to the moon for the first time to prepare to take off.
The comic doesn't represent the preparations for the Apollo launch entirely accurately, however. Prior to their "departure" to the launch pad, the Apollo 11 astronauts had woken up at 4:15 AM, and after a 25-minute breakfast had spent at least an hour and a half getting into their spacesuits.  For regular travel on an airplane or other modes usually no more than a few minutes preparation is needed, for instance, to load luggage in a car or wait for a cab.  What's more, because all activity took place at Cape Canaveral, the "trip" to the launch site took only 8 minutes, and the crew began to take their seats in the Saturn V rocket only a few minutes later, at 6:45 AM.  Thus they were locked in the capsule for about two-and-a-half hours prior to launch.  For normal travel, people will only be in their seats for a few minutes before departure, or for large aircraft maybe a half an hour while it loads.  Thus the total time from beginning to get ready to liftoff was about five hours, which in fact is longer than less complicated activities like air travel. [ citation needed ] This is though still significantly shorter than you would think preparation for a journey over a distance of almost 10 times around the Earth, each way, and in significantly more dangerous conditions, would take.
The alt-text is a reference to Global Entry , a United States Customs and Border Protection program that allows US citizens to quickly proceed through customs checks when arriving from overseas, instead of waiting in a long line to present a passport. The Global Entry program also allows for access to the TSA PreCheck program, which allows for expedited security screenings, but here the word "Global" is literally true of an astronaut returning to earth, not a marketing phrase.
In the case of the Apollo astronauts, their return to the earth involved re-entry into the atmosphere (technically called Atmospheric entry ), and of course global is another word for things relating to the earth.  So the Apollo astronauts could be said to have undergone "global entry" on their return.  The joke is that since they have "Global Entry" privileges, the astronauts did not need to arrive as early to the Saturn V launch site.
[Three Cueball-like astronauts with space helmets are walking toward the back side of a van with the rear door open. There is a logo with text on the side of the van. The front of the van is off-panel. Above them is a time and below that a description.] 6:27 AM Crew departs for launch site Logo: NASA
[A rocket launch pad with the rocket in the process of taking off, having lifted its exhaust to about a third of the height of the support tower. Smoke is billowing everywhere around the launch pad from the exhaust of the rocket. Above the rocket is a time and below that a description.] 9:32 AM Liftoff
[Caption beneath the panel:] I know I tend to arrive too early at the airport, but it still weirds me out that Neil Armstrong left for the launch site just three hours before departure.


Cell Phone Functions

Explanation:
This comic pokes fun at the ever-increasing function of smartphones and their users' reliance on them through an unusual horizontal bar graph showing what services a smartphone provides (or will provide) that were performed by other devices in the past and when the switch took or will take place. It starts sensibly: Calling, browsing the Internet, and taking pictures are the most prominent examples of tasks that many if not most people use a smartphone instead of a specific device nowadays. The next item, newspaper, extends the Internet's capabilities (either from within the mobile browser or as a dedicated app), and the next, flashlight, repurposes the phone camera's flash unit; both are now commonplace features of smartphones. Some people even use their smartphone as the remote for their TV (either via RF wireless [e.g., WiFi] for smart TVs, or via their phone's infrared port) or to pay in stores using payment providers like Google Play Wallet, Samsung Pay, or Apple Pay, which utilize the near-field communication functionality of modern smartphones. A few cars now support using a phone app instead of a key fob, rendering yet another item obsolete; apparently, Randall just started using this feature in his car, as this item is in the very recent past in the comic's diagram.
Then the comic drifts off into smartphone capabilities either not yet possible or likely never to be possible. These capabilities are right of the "now" mark, meaning Randall has not switched to using a smartphone for them: One cannot currently use a phone app as a dog leash, nor as an adhesive bandage. While using a phone as a steering wheel is possible (likely interfacing with the car's self-driving features), it would be a reversal of current initiatives to prevent drivers from using cell phones while driving. Things get increasingly odd, to the point where a smartphone is allegedly used as a toothbrush. Several items would require physical changes to the phone and not just repurposing existing capabilities, such as operating as a cheese grater, stapler or nail clipper, which would make the phone look and feel more like a Swiss Army Knife instead. [ citation needed ]
The title text continues this path by continuing the list of objects his phone will supposedly replace. These include a "tazer" (a misspelling of taser ), a fire extinguisher, a bird feeder, and toilet paper, continuing the path of absurdity the comic implies with its supposed future uses for a phone.
[A graph with time on the x-axis and items Randall replaced with his smartphone on the y-axis. For each item, the time he (allegedly) replaced it is marked; the marks form a jagged line down the graph, roughly sorted by when he switched. The regions are marked] I have a specific device for this [and] I just use my phone [items where the switch-over date is in the past:] Telephone Web Browser Camera Newspaper Flashlight TV Remote Credit Card Car Key [items where the switch-over date is in the future:] Dog Leash Steering Wheel Band-Aid Cheese Grater Stapler Nail Clipper Electric Drill Toothbrush
[The x-axis (time) shows at point labelled as 'now' roughly halfway along the graph, a grey dashed line runs vertically down the whole graph. Car Keys have just been replaced by a phone, all other items listed below that have yet to be replaced. For the most part the gradient of the trend is constant at around -1. The last item (Toothbrush) is replaced before the penultimate item (Electric Drill)]


How Old

Explanation:
Another comic of the tips type , this time regarding one of Randall's problems, social interactions , this time including an interaction tip .
White Hat introduces his dad to Cueball , who then expresses a reaction more typical of people being introduced to children, by saying Aww, how old is he?
When introduced to a young kid, saying "aww" is accepted as normal, because the speaker thinks the little child is cute. The speaker also wishes both to know the age of the kid and to give the kid a chance to answer this question.
But when meeting someone older this would feel very awkward, and Randall, indicating he is very awkward around other (normal) people, continues to make this type of comic about problems with social interactions. Hence for others with his problems, this comic gives an interaction tip in the caption, letting you know that How Old? (the title of the comic) is a common question to ask only when introduced to kids, not to older people such as elderly parents. Another excellent example of how Randall also doesn't know how to speak with people with children can be seen in 1650: Baby .
White Hat's father is wearing a sailor cap like the old version of Cueball in 572: Together and as other old people both in 586: Mission to Culture and 1910: Sky Spotters .
In the title text, Cueball continues down the road to awkwardness by saying other things normally reserved for meeting kids. Here he notes that he has actually met White Hat's father before, but so long ago that he since has changed height. For kids this usually means they have grown taller, but old people, who have long stopped growing, will over time become more compressed and lose height. So apart from saying that he remembers when White Hat's father was thiiiis tall , he also holds his hand an inch (2–3 cm) above the father's head to indicate this age-related height loss. For a growing child, he would instead have held his hand some distance below the top of their head.
This interaction would be really embarrassing for White Hat and his father, as being made aware of aging is usually not something people like to be confronted with by someone they hardly know, and being treated like a child is embarrassing. [ citation needed ]
[White Hat holds his hand out towards a man with a sailor-cap standing to the left in the image while addressing Cueball standing to the right.] White Hat: I'd like you to meet my dad. Cueball: Aww, how old is he?
[Caption below the panel:] Interaction tip: This is a common question to ask parents about their kids, but for some reason in the other direction it's weird.