Hofstadter

Explanation:
Douglas Hofstadter is an American author who has written several books about philosophy, mathematics, and science. He is perhaps most famous for his book Gödel, Escher, Bach which explores "strange loops," or self-referential systems . "Meta-" is a Greek prefix meaning "outside" or "beyond." As an adjective, "meta" informally refers to anything self-referential, like the last phrase of this sentence. An example of the use of such a term can be found in 1313: Regex Golf .
At first reading, the six word autobiography in the second panel, "I'm So Meta, Even This Acronym", may seem unfinished, however the clue is in the final word. An acronym is an abbreviation formed by the initial letters of a series of words, and reading the first letter of each of the six words in order yields "ISMETA", completing the sentence and setting up the self-reference. Hofstadter himself did something similar in Gödel, Escher, Bach in the chapter "Contracrostipunctus", where the first letter of each line spells out the phrase " H ofstadter's C ontracrostipunctus A crostically B ackwards S pells J .S.Bach" - and taking the first letters of each word in that sentence backwards does indeed spell " J.S. BACH ".
This comic is probably a reference to Six-Word Memoirs , a project launched in 2006 in which people "tell their life story in just six-words".
This comic may additionally be a reference to the meme "explain <whatever> in six words", which was making the rounds at the time.
In the title text, a reference implementation is, broadly, an example of how to implement some feature during the software development process. In this case the feature is a self-referential joke, and the sentence itself is, correctly, self-referential.
Hofstadter has been referenced before, in the title text of 555: Two Mirrors and 608: Form . Furthermore, his famous book has been directly spoofed in the title of 24: Godel, Escher, Kurt Halsey . Finally, the self-reference reference ("IS META") is also a typical concept used most famously in 688: Self-Description but also in several other comics .
[Cueball sits at a desk, working on a laptop. Megan approaches the desk and picks up a tiny book.] Megan: What's this? Cueball: Douglas Hofstadter's six-word autobiography. After all those 700-page tomes, I guess he wanted to try for brevity. Megan: Huh. Let's see...
[Close up of Megan, reading the tiny book.] Book: I'm So Meta, Even This Acronym
[Full shot of Cueball and Megan again. Megan looks down at the tiny book in her hand.] Megan: ...whoa. Cueball: I think he nailed it.


Google+

Explanation:
At the time of the comic's release, Google+ was a new social network announced by Google on June 28, 2011. When it launched there were many tech articles written about G+, which appears to look and/or function similarly to Facebook. In the first panel, Megan describes G+ as 'not Facebook '. Facebook is a popular social networking site. [ citation needed ] She then describes G+ as being like Facebook.
After Cueball thinks about it in the second frame, he comes to a realization in the third frame that a social network like Facebook, but not related to Facebook is all he really wanted. This is in reference to the backlash that happens every so often wherein people grow tired of Facebook, its arcane policies, its cavalier attitude toward user privacy and/or its general disdain for end users, and people want to leave Facebook, but have no comparable platform to move their social networking to.
The title text uses "you'll never be able to convince your parents to switch" as both point and counterpoint in an argument, since this fact has both negative (your parents won't see posts you want them to see, and won't be able to post things for you to see) and positive (your parents won't see posts you don't want them to see, and you won't have to worry about keeping up with their posts) implications.
On April 2, 2019, Google shut down Google+ for consumers. It is still available for users with a G Suite account.
Megan: You should join Google+! Cueball: What is it? Megan: Not Facebook! Cueball: What's it like? Megan: Facebook!
[Cueball considers.]
Cueball: Oh, what the hell. Cueball: I guess that's all I really wanted. click


Tween Bromance

Explanation:
Apparently, Randall hates some ridiculous neologisms. Cueball seems to be dictating a "Tween bromance" story or novel to Megan , who is possibly typing it up. He is including all the words that get to Megan in a sequence. Megan is just annoyed and starts to shriek in rage; considering Cueball keeps speaking more annoying words in the title text, that seems to have been the point.
Like this comic fills a sentence with (gross) neologisms, 550: Density crams a sentence with memes.
According to 1485: Friendship , Randall doesn't like the word bromance much either. Uncomfortable synonyms are also seen in 1322: Winter and 2352: Synonym Date .
[All of Cueball's lines are overlaid over the entire comic; the panels listed are merely the ones directly under each sentence fragment.] [Cueball is standing smugly behind Megan, who is seated in front of a computer and typing.] Cueball: By my guesstimate,
Cueball: my frenemy yiffed so hard
Cueball: her moist taint made [Megan's eye twitches.]
Cueball: her panties preggers! Megan: STOP IT STOP IT!


YouTube Parties

Explanation:
A YouTube party is when a group of people show each other YouTube videos. The problem with YouTube parties is that no one pays attention to the video that's playing; instead, each person is thinking of the video that they personally want to play next.
You can see analogous behavior at any get-together where couples (parents) are telling stories about their kids. Nobody cares about anybody else's kid; they are just waiting (not even listening) until they get the chance to talk about their own offspring.
The joke seems to be that everybody is doing this, but it is unclear whether they realize it. They each seem to be under the delusion that the others will be fascinated by "their" video (or child's accomplishments), even though the evidence strongly suggests otherwise. Possibly they don't care about that either; they just want an audience, even an unwilling one.
This may be defensible where kids are involved, because the parents could reasonably feel that the accomplishments of their children reflect well on themselves. However, the people in the YouTube party didn't create the videos, they just found them. Which makes their behavior (or perhaps YouTube parties in general) even more inane and pointless.
The title text reiterates this point. The speaker is reminded of another video that is so superior to the one currently playing that we should find it and watch it immediately. We can always go back to the current video later (if anybody still remembers, that is; and according to the comic above no one will want to remember it).
[Cueball and a group consisting of three Cueballs and one Ponytail are standing in a dark room around a table. The group and Cueball are illuminated by a laptop on the table.] [Caption above the panel:] The problem with YouTube parties: Cueball (thinking): This video is blowing their MINDS. Group (thinking): Oh man, I know what video we should watch once this is over.


Delivery Notification

Explanation:
In the US, when the package delivery company UPS (or other package delivery companies) knocks on your door or rings your doorbell and cannot reach you, they leave a delivery attempt notification stuck to your door. These may be for packages that require a signature, such as expensive electronics. An example is shown in the first panel.
This comic hints that the threshold for the UPS delivery person to leave such a notice is unreasonably low. The delivery personnel made only a token effort to deliver the package (which, incidentally, is their only actual job) before posting the yellow delivery notification and unconcernedly driving away to their next delivery (or, more likely, their next yellow-delivery-notification-posting).
After missing the delivery, Cueball (who is directly referencing The Lord of the Rings ) asks the Elves to reforge his sword in order to go on a quest to retrieve his new laptop. In The Lord of the Rings , Aragorn (accepting his role as the heir to the king of the West) had the sword of Elendil , called Narsil , reforged (which symbolizes the reuniting of the race of man under one leader). Cueball obviously views the UPS building as a dangerous and impenetrable fortress, and possession of such a sword is the only way to guarantee success in his quest.
Ironically, when the Elves come to deliver the new sword, the delivery elf is unable to notify anyone in the house, and simply leaves another delivery notification.
In the title text, Rivendell is one of the home of the Elves, where the broken shards of Narsil resided, with Elrond and his elves. Unfortunately for Cueball, the sorting depot of Rivendell has the same, limited opening hours as the UPS.  It is apparent that Cueball will not be getting his laptop in time for his flight.
[The first panel is a UPS InfoNotice®. Most of the text on it is just scribbles, though the company logo and header is clear.]
[Cueball opens their door to see the InfoNotice® stuck on his door.] Cueball: What! I've been here all day! Cueball 2 (off-screen): Huh? Cueball: They have my laptop.
[Cueball and Cueball 2 are standing next to each other. Cueball has his arms to his sides, in annoyance.] Cueball 2: So get it tomorrow. Cueball: I fly out in the morning and they don't open till noon! Cueball 2: Sucks.
[Cueball stands, working on a laptop.] Cueball: It's right there . I can see the UPS building on the map. Cueball 2 (off-screen): Ok...
[Dramatic zoom to the Cueball's upper torso and face, along with clenched fist.] Cueball: My laptop is there. Cueball: It's mine . Cueball: I'm going to get it.
[Even more dramatic zoom! Cueball's face fills the panel.] Cueball 2 (off-screen): They won't let you. Cueball: Who are they to keep from me what is mine? Cueball 2 (off-screen): Dude, they—
[Zoomed out on Cueball, who spins around, raising a finger.] Cueball: A quest is at hand! Cueball 2(off-screen): Security's gonna throw you out. Cueball: I fear neither death nor pain. But I will not go unarmed.
[Three inset panels overlap, in a montage format.] [Elves in long robes stand around a table, on which lies a broken sword.] Light the beacons and send word to the Elves. They must reforge the sword of my fathers.
[An Elf beats the sword together on an anvil.]
[An Elf rides a horse, silhouetted by the full moon.] Ere dawn, I will go forth to the Sorting Depot.
[The Elf knocks at the door, sword in scabbard held under arm.] Knock knock knock knock
[Cueball opens the door, to find a second InfoNotice® stuck on top of the first. The Elf is gone.]


Fight Club

Explanation:
Fight Club is a movie starring Brad Pitt and Edward Norton that was released in 1999, based on the novel of the same name by Chuck Palahniuk. It included this oft-quoted and parodied line: "The first rule of Fight Club is you do not talk about Fight Club."
The movie has been fiercely debated by critics, primarily regarding whether it makes a sophisticated philosophical statement about society and consumerism or whether it is just a movie with lots of fighting and mischief . Randall explains his position in the title text, claiming that he lies somewhere in-between and does not want to debate this issue with others.
"This conversation is over" is also a line from the movie, in the scene where the Narrator (Edward Norton) is arguing with Marla Singer (Helena Bonham Carter) while Tyler (Brad Pitt) tells the Narrator what to say from the bottom of the basement stairs.
Friend: But Fight Club isn't really about fighting. It's about the way society— Cueball: Nope, don't wanna hear it. Friend: But it says consumers are— Cueball: This conversation is over.
The first rule of talking to me about movies is do NOT talk about Fight Club.


Strunk and White

Explanation:
The 1918 writing style guide The Elements of Style , by Cornell University professor William Strunk Jr. and New Yorker writer E.B. White (perhaps better known as the author of Charlotte's Web and Stuart Little ), is commonly referred to as " Strunk & White ". In this comic, the current editors of Strunk & White are clarifying a matter of style pertaining to the style guide, an instance of meta humor , a recurring theme in xkcd .
Erotic fan fiction is a genre of writing in which fans make up erotic stories involving characters from non-erotic stories. " Slash fiction " is a subgenre that pairs characters of the same sex: These pairings are denoted by using the "/" to separate the paired characters, hence the name "slash fiction". This convention is generally thought to originate with the Kirk/Spock pairing in Star Trek fan fiction, wherein "K/S" was used for such romantic or erotic works of fan fiction, while "K&S" was used for non-romantic works. This comic imagines a similar distinction being necessary for " Strunk & White " vs. "Strunk/White".
The title text comments that authors of Strunk/White fan fiction will most likely have read The Elements of Style , which makes them better writers.
[Hairbun, with glasses, sits behind a desk typing on a computer. A line goes from the keyboard indicating that the text above is the one she types. Behind her stand Cueball with a book in his hand, and a man with male-pattern baldness holding up a smoking pipe.]
Dear Internet, We, the current editors of Strunk & White's The Elements of Style , must—with great reluctance— clarify a point of orthography:
"Strunk & White" should be used for the style manual and "Strunk/White" for the erotic fan fiction pairing.
E.B. White is mentioned again in the later comics, 2162: Literary Opinions and 1087: Cirith Ungol .


3D Printer

Explanation:
With the ongoing development of 3D printing technology, the cost of low end 3D printers continues to reduce steadily, and the complexity of modelling and producing components is becoming easier. These factors, among others, means that 3D printers are beginning to be found in homes, rather than exclusively in businesses. Ponytail & Cueball are discussing the improvements and expect widespread deployment soon.
Spam emails promoting penis-enlargement products are very common, and often show images of unnaturally large penises to advertise how effective they are. The adverts prevalence and aggressive marketing techniques have made them a well known staple of email inboxes, though the improvement of spam filters has increasingly banished them to the spam folder.
Cueball and Ponytail predict that the spam producers will quickly jump on the opportunity presented by the widespread prevalence of 3D printers, and start advertising their wares with 3D printed phalluses. Usually someone would have to proactively choose to print out a spam email, but it wouldn't be difficult to imagine a scenario where the email contains malicious code which automatically prints them a huge phallus.
In the title text, Better Homes and Gardens is an American magazine that, as the name suggests, shows you how to make your home and garden better often by reusing common household items in new and innovative ways. Acrylonitrile-butadiene-styrene (or ABS) is a light-weight and moldable plastic which makes it perfect for 3D printers.
[Two people before a 3D printer, one with a wrench.] Cueball: 3D printers are getting incredible. Ponytail: I think we're not far from widespread deployment.
Ponytail: And you know what that means.
Cueball: Spam containing actual enlarged penises? Ponytail: I give it a week.


Cell Phones

Explanation:
This comic is a good explanation of the correlation/causation fallacy, where one party states two unrelated events and posits that they must have influenced each other.
After hearing about the "Cell Phones Don't Cause Cancer" study, which refutes a claim made by the World Health Organization (just Google the debate or check out Wikipedia's article on it , the comic doesn't focus much on it), Black Hat plots "Total Cancer Incidence" per 100,000 and "Cell Phone Users" per 100 on the same graph. The graph in frame 3 shows an exponential rise in cancer in the 70's and 80's, followed by an exponential rise in cell phone usage in the 2000's. Black Hat reverses the correlation/causation fallacy, and comically comes to the conclusion that cancer causes cell phones .
The comic highlights a well-known fallacy known as post hoc ergo propter hoc , often shortened to simply post hoc. The Latin translates to "after this, therefore because of this," referring to the common mistake that because two events happen in chronological order, the former event must have caused the latter event. The fallacy is often the root cause of many superstitions (e.g., a person noticing he/she wore a special bracelet before getting a good test score thinks the bracelet was the source of his/her good fortune), but it often crosses into more serious areas of thinking. In this case, the scientific research community, which often prides itself on its intellectual aptitude, is gently mocked for being nonetheless prone to such poor reasoning all too often. The different possibilities are generally known as causation, when one thing is proven to cause another, or correlation, when changes in one thing are aligned with changes in another, but there is no proof that they are directly related.
The title text refers to the way Black Hat holds the laptop in panel 2. Being that Cueball (and Randall, for that matter) are quite into computers, the potential damage to a laptop screen either from the weight of its lower body or the pressure of the user's fingers on the LCD screen is enough to make him squirm in discomfort. The risk of dropping the computer is also present.
[Cueball holds a cellphone. Black Hat is sitting at a desk with a laptop.] Cueball: Another huge study found no evidence that cell phones cause cancer. What was the W.H.O. thinking? Black Hat: I think they just got it backward.
[Black Hat turns towards Cueball in an unframed panel, holding the laptop with one hand by the upper edge of the screen. Cueball is not visible.] Cueball: Huh? Black Hat: Well, take a look.
[There is a plot of total cancer incidence and cell phone users. Cancer rises from 1970 to 1990, then stays relatively steady. Cell phone use rises from roughly 1984, and steeply after 1990, to the present.]
Cueball: You're not... There are so many problems with that. Black Hat: Just to be safe, until I see more data I'm going to assume cancer causes cell phones.


Time Vulture

Explanation:
This comic is about the time vulture (hence the title), a fictional creature made up by Randall . Cueball notices that his Cueball-like friend is followed by a time vulture, making the exclamation Dude, you've got a time vulture.
The primary food source for vultures is carrion, or rotting meat. A time vulture, as explained by Cueball, is a type of vulture that can live for millennia , spending very little energy and it can even slow down its internal clocks so time speeds past, a kind of forward time travel, to the point where its prey dies. In this way, it can thus always wait long enough for the prey to die of natural causes no matter how long it takes, as seen from the prey's point of view. So in principle they kill their prey by using aging, as Cueball explains, although in fact, like any vulture, they just find prey that has already (almost) died, as from their point of view every living thing is just about to die. But as with other vultures, they do not participate in the actual killing. Time vultures thus just need to locate and find any one living creature (of a reasonable size), then it becomes it’s prey as it then just waits until it dies, spending hardly any energy while it waits. Real soaring vultures can also stay afloat for considerable time spans without actually using any energy as they just float on thermals .
Thus the time vulture will now keep soaring over Cueball’s friends head for the rest of his life, or until they travel on an airplane (airplanes typically cruise at an altitude too high for a vulture to fly over them, although it is of course possible that the vulture could board the plane as well), and then when he dies (whenever and of whichever cause), it will descend and feast on his carcass. This should, in principle, not make any difference to the friend, since most people already live with the knowledge that they will eventually die [ citation needed ] , and that their body will end up being destroyed one way or another. Typically it will not be caused by vultures, but for instance by the fire of the Crematory or by the decomposition caused by small animals and germs in the earth we are buried in.
However, it is not very nice to be reminded of this every living second of the rest of your life thus the consternation of the friend and his question and statement; But what if the prey doesn't die? and I'm not about to die...
At first, the question doesn’t make sense since there are no known examples of terrestrial animals (including humans) that are large enough to matter as prey for a vulture and can survive through the several millennia that a time vulture can wait. The few species that can live that long and grow at least as large as vulture prey, such as the 2,384 acre (965 hectare) "Humongous Fungus", an individual of the fungal species Armillaria solidipes in the Malheur National Forest , thought to be between 2,000 and 8,500 years old [1] [2] , and a Great Basin bristlecone pine ( Pinus longaeva ) measured by ring count to be over 5000 years old. [3] , are stationary, such as fungi and plants, or aquatic, such as coral and sponges.  Thus, the moving land species large enough to be attractive as prey will always die within the lifespan of the vulture (as Cueball tries to explain).
However, the question actually does make sense, because the prey does not have to outlive the vulture to avoid being eaten by the vulture; it simply has to live long enough to get to an airport, get through security screening, and board a flight that goes either too fast or too high for the vulture to follow.  Therefore, the vulture would get to eat the prey only if the prey died on the way to the airport, while standing outdoors in line for security screening, or while walking from the terminal to the airplane (if passengers board outdoors instead of using a passenger boarding bridge (Jetway) ).  It is possible that the prey might not die this soon, unless security screening lines exceed the maximum human lifespan of approximately 120 years.
And because the time vulture can slow down its internal clock, in its point of view, everyone who ever says "But, I'm not about to die", would say so right before they die; actually anything a person ever says after the time vulture has locked on to that person, happens just before they die as seen from the vulture's point of view. In humans' point of view, it could be many years after the statement was made, but for the time vulture, a human lifespan only lasts a mere moment.
Of course, since a human can travel a considerable distance in this time, even around the world, the human would be traveling at an extremely high velocity from the vulture's perspective, so the vulture would be unable to keep up and the human would escape. In a more extreme fashion, since the vulture’s perception of time is significantly slowed, it would be more simple to buy a rifle and kill the Time Vulture.
It is thus really more of a philosophical comic about the fact that we all have death waiting for us, you could say it soars above our head and just wait for it to happen. And in relation to the deep time of the geology of the Earth or the expansion of the universe, the time it takes for people to live their lives is hardly worth mentioning...
In the title text it is stated that all real life vultures are actually a kind of time vultures, as real life vultures also sometimes spot a dying animal, not quite dead yet, and then wait for this prey to die. But time vultures are able to wait for millennia for their prey to die, whereas regular vultures do not have that kind of time, before they need to feed or land, thus the comment that some vultures have more patience than others.
Real vultures and their preying habits was referenced in 1746: Making Friends , directly in the title text.
[Cueball is watching a large black bird, with apparently fractal wings, which hovers above his Cueball-like friend who walks towards Cueball and now turns to look at the bird over his shoulder.] Cueball: Dude, you've got a Time Vulture. Friend: Holy crap! What is it?
[Zoom-in on Cueball who now looks at his friend who are now standing close to Cueball looking up at the bird off-panel.] Cueball: They're predators that use aging to kill prey. Friend: Huh? What do you mean?
[The panel zooms in on the Cueball's face. The friends reply comes from off-panel.] Cueball: They live for millennia and use little energy. They can slow down their internal clocks so time speeds past. To hunt, they lock on to some prey, and when it stops moving, they eat it. Friend (off-panel): But what if the prey doesn't die?
[Zoom out to Cueball and his friend that now look at each other.] Cueball: I don't think you quite understand. Friend: I mean, I'm not about to die... Cueball: From the vulture's viewpoint, everyone says that moments before they do.


Standards

Explanation:
For any engineering task, there are numerous ways a given problem can be solved. The more complex the task, the more room for diversity. That's all well and good for a one-off problem, but if a design is meant to be iterated over time, or if an entire industry is solving that same problem, part reuse and interoperability become issues to deal with. Technical standards thus came to exist so that industries could avoid wasting resources reinventing the wheel , whilst offering their clients a certain amount of simplicity and compatibility between vendors.
But, standards have issues of their own. They don't accommodate every use case , they might have restrictions or royalties attached, and people tend to be plagued by Not Invented Here syndrome . So, competing standards have a tendency to arise to address different perceived needs. After a while, the market for competing standards gets messy and hard to follow, and integrating systems built around competing standards gets burdensome. As a result, someone eventually takes on the challenge of creating a universal standard that everyone can rally around.
This almost never works. In many cases, a new standard fails to displace the incumbent standards, eventually loses funding and support, and thus becomes a relic of history. In many other cases, it only penetrates far enough to survive, ironically making the situation messier. The latter situation often ends up becoming cyclical, with new standards periodically rising and failing to gain traction.
Three examples are given at the top of the comic: AC chargers , character encoding and instant messaging .
The title text mentions mini-USB and micro-USB, which were different standards used in 2011. As of 2019 for most applications of small USB ports (especially for charging / connecting cell phones), mini USB has lost most of its relevance and micro USB is competing with USB-C, as well as some solutions only used by single companies (such as Apple).
Not all standards are created equal. In the development of standards , private standards adopt a non-consensus process in comparison to voluntary consensus standards. Private standards in the Information and Communications Technology (ICT) sector and the agri-food industry (governed by the Global Food Safety Initiative ) are discussed in a publication from International Organization for Standardization.
How Standards Proliferate (See: A/C chargers, character encodings, instant messaging, etc.)
Situation: There are 14 competing standards.
Cueball: 14?! Ridiculous! We need to develop one universal standard that covers everyone's use cases. Ponytail: Yeah!
Soon: Situation: There are 15 competing standards.


Mimic Octopus

Explanation:
This comic is a parody of fish and sea-life identification charts, referencing the mimic octopus which, as the name implies, is able to mimic other animals, so all animals and objects found in the sea could actually just be such an animal.
The identification chart for South East Asian sea life shows 13 creatures mimicked including eight individual fish (two of which are not yet recognized) and other objects and animals. In order, top-to-bottom, left-to-right: A Moorish idol (Gill, from Finding Nemo ) , unknown, a rockfish , a clownfish , unknown, a lionfish , a shark , a sea lily , an angler fish , an anchor , a submarine , a scuba diver and school of 11 fish . Finally there is an octopus , but rather than being the mimic octopus in its natural form it's actually two of them each mimicing part of an octupus.
The Orson Scott Card novel that the title text refers to is Lost Boys : "A withdrawn eight-year-old in a troubled family invents imaginary friends who bear the names of missing children" (Publisher's Weekly). The part of the story that Randall is referring to (Chapter 7, Crickets) involves a situation where the protagonist, Stevie, is given a C grade for an otherwise impeccable diorama featuring underwater animals involving clay sculptures (when only a poster would have sufficed) and a well-written presentation supposedly because the other children had destroyed the diorama before the end of the day. To make matters worse, his teacher, Ms. Jones, had made fun of his project and given the ribbon for first prize to someone else.
On inquiring about, his father, Step, found out that the principal, Dr. Mariner, had already made the decision to hand Stevie the blue ribbon for first prize as she had reviewed the project before it had been destroyed, but Ms. Jones had secretly overruled her behind her back by announcing that another child (JJ) would receive the ribbon. So, the next day he met up with Ms Jones after school to have a word on the grading of his project. Needless to say, they ended up arguing about minor issues, with Mrs. Jones justifying the reason for her decision on, among other things, the definition of a 'depiction', whether or not the amount of content was defined by the word count or the number of pages and of the importance of putting the report in a plastic cover. The argument finally comes to a head when Step points out that there was only one red mark on the project report, and that concerned an 'incorrect' pluralization of the word 'octopus'
“But Mrs. Jones, surely you know that the plural of “octopus” is either ‘octopus’, with nothing added, or ‘octopuses’.” “I think not,” said Mrs. Jones. “Think again, Mrs. Jones.” She must have realized that she was not on firm ground here. “Perhaps ‘octopuses’ is an alternate plural, but I’m sure that ‘octopi’ is the preferred.” “No, Mrs. Jones. If you had looked it up, you would have discovered that ‘octopi’ is not the preferred spelling. It is not a spelling at all. The word does not exist, except in the mouths of those who are pretending to be educated but in fact are not. This is because the ‘us’ ending of ‘octopus’ is not a Latin nominative singular ending, which would form its plural by changing to the letter ‘i’. Instead, the syllable ‘pus’ in ‘octopus’ is the Greek word for ‘foot.’ And it forms its plural the Greek way. Therefore ‘octopoda’, not ‘octopi’. Never ‘octopi’.” “Well, then, octopoda. Your son’s paper said octopuses.” “I know,” said Step. “When he asked me the correct plural, I told him octopoda. But then he was still uncertain, because my son doesn’t think he knows something until he knows it, and so he looked it up. And to my surprise, octopoda is only used when referring to more than one species of octopus, rather than when referring to more than one actual octopus. What Stevie put in his paper is in fact the preferred dictionary usage. Which you would have known, too, if you had looked it up.”
After proving his case that his son did indeed deserve an A grade, he then threatened to bring the matter to the attention of the principal. He then warned Mrs Jones that while he wanted the grade to remain unchanged, he wanted her to inform the class that the ribbon would be awarded to Stevie, before revealing that he had been recording the conversation all along. And, after this, after Mrs Jones came crying for forgiveness before leaving, Step realized how vulnerable she was and how she was channeling her frustration at one particular student in each class to find some relief from that.
According to the Merriam-Webster Dictionary , 'octopi', 'octopuses', and 'octopodes' (UK English) are all correct plural versions of "octopus." Supposedly, Randall would very much like the word 'octopi' to remain unrecognized by major dictionaries as otherwise it would lessen the magnitude of the climactic conclusion of this argument by rendering Step's mockery of Ms. Jones' perceived intellectual superiority factually invalid. This also offers another reason why the octopus in the chart is named two mimic octopuses , so Randall can use the correct pluralization of the word in the comic. This is an example of a comic where the title text seems more important to Randall than the actual comic.
It should be noted that, at least according to Etymology Dictonary , Octopi is wrong for exactly the reasons that Step lists and first appears over 60 years later.
[Captions above the panel:] Southeast Asian Sea Life Identification Chart [The chart consist of 14 black silhouettes which includes eight individual fish and several other object/animals. From top left: A Moorish idol, unknown fish, a rockfish, a clownfish, unknown fish, a lionfish, a shark, a sea lily, an w|angler fish, an anchor with chain, a submarine, a scuba diver, a school of seven large and four small fish, and and at the bottom right a silhouette of an octopus displaying eight arms and a tilted head with large white eyes. All 14 are labeled the same except the octopus:] Mimic Octopus Mimic Octopus Mimic Octopus Mimic Octopus Mimic Octopus Mimic Octopus Mimic Octopus Mimic Octopus Mimic Octopus Mimic Octopus Mimic Octopus Mimic Octopus Mimic Octopus Two Mimic Octopuses


Speculation

Explanation:
During a basketball game, the players discuss the nature of universal conformity. Facebook and Google+ are competing social networks ; at the time of this comic many people were switching to Plus over Facebook leading many to speculate that Facebook was in decline and that Plus would soon be the dominant social network. As of 2019, it seems that Facebook has successfully held its position as the Default Social Network™, while Google Plus was a colossal blunder for Google and was finally sunset for consumers in April 2019.
The two players seem to have a disagreement over this. One player states that it would be ridiculous to expect everyone to move to Plus. The other player denies the notion that they have to, stating that he values his personal preference over conformity. He supports this idea by saying that his mother still uses AOL and other people continue using IRC and that if each time a new dominant social network emerged and everyone switched to it, neither of these things would stick around.
They are interrupted when they pass the ball to Black Hat , who immediately shoots it with a crossbow bolt. Their arguments and rather intelligent discussion are derailed by the absurdity of Black Hat's reaction, which is both humorous and puts the issue in stark contrast.
Black Hat neither joins in the discussion nor does he participate in the game. It seems that any offer to participate in either is met with a blunt and clear denial. He is simply not a conformist.
A possible explanation for the joke is that while tech geeks or Google enthusiasts might discuss whether the world will move from Facebook to Plus, a number of people might simply ignore the debate and "shoot" the discussion dead by just ignoring the existence of anything that isn't Facebook.
In the title text, Black Hat continues to provide an example of his tendency to play by his own rules. A clay pigeon is a clay disc that is thrown into the air and serves as a target on a skeet shooting range. Participants are expected to shoot the pigeons with a shotgun but Black Hat would rather capture the clay pigeons and shoot them from a very close range. (This is made even more humorous by the excellent crossbow skills he shows in the comic.) This practice eventually got him expelled from the shooting range. It is unclear whether Black Hat was good at shooting clay pigeons from farther away.
[Two Cueball-like guys are playing basketball. The right guy (Cueball) attempts to throw the basketball through the hoop, but it bounces off down to his friend. To the right Black Hat has his back to the other two while he is looking at his phone.] Friend: Do you seriously think everyone will move to Plus? It was hard enough getting them on Facebook.
[The friend has caught the rebound and now passes the basketball back to Cueball. Black Hat is not shown.] Cueball: Do they have to? Cueball: My mom still uses AOL—it doesn't mean my social life has to happen there.
[Only Cueball is shown. He passes the basketball to the right towards the off-pannel Black Hat.] Cueball: Universal adoption isn't everything. I mean, IRC is still—
[Zoom in on the basketball as an arrow pierces the ball, forming a slight depression.] Thunk
[Cueball looks to Black Hat who has a crossbow in one hand, he is still looking at the phone in his other hand. The ball with the arrow lies between them.] Cueball: You're not really the "catch" type, are you? Black Hat: I am not.


Days of the Week

Explanation:
As explained in the image, the graph is a polar graph, charting the relative strengths by which certain phrases are associated with certain days of the week. The closer a phrase comes to the center of the graph, the less the phrase is associated with whatever day of the week that is. Conversely, the further out a phrase is, the more associated with that day of the week it is.
Perhaps the clearest example of this in the above graph is the ladies night line, which has such a strong peak on Wednesday that it goes clear out of the bounds of the picture. Likewise, church is so strongly associated with Sunday that it goes off the chart there.
Also of interest are the less eccentric orbits, for instance "big day" and "so drunk." The fact that these don't clearly peak on any one day indicates that (according to Google, at least) big days are spread out fairly evenly throughout the week (with a minimum on Mondays), and so drunk tends to peak on weekends, though it seems fairly evenly split between Fridays and Saturdays.
Mentioned in the title text is Rebecca Black 's viral pop hit, Friday , which received considerable negative attention and ridicule for its terrible songwriting and performance. It peaks so far out that no perspective which would show it would be of any use, since many parodies have been made of the song since.
[The whole comic is a single panel, with a circular diagram of the days of the week.]
Polar graph of what stuff happens on which days, based on number of Google results for phrases like "company meeting on <day>." The relative frequency of <day> in <phrase> is shown by the distance from the center at which <phrase>'s line crosses <day>. Each curve is normalized to have the same number of total hits - they're not on the same scale.
(Not easy to reproduce the actual plot, these are the phrases, in order of popularity on Wednesday.) 1. <day> is ladies night 2. announced <day> 3. company meeting on <day> / company meeting <day> 4. due on <day> 5. got laid <day> 6. drunk on <day> /  so drunk <day> 7. <day> is the big day 8. Church <day> 9. got my period <day> 10. we broke up on <day> 11. <day> sucked
[Thursday, from most common to least common: 11, 2, 1, 3, 9, 4, 5, 7, 10, 6, 8] [Friday, from most common to least common: 10, 4, 6, 7, 5, 9, 11, 3, 2, 1, 8] [Saturday, ditto: 6, 7, 5, 11, 9, 10, 8, 3, 2, 1, 4] [Sunday, ditto: 8, 9, 7, 11, 10, 5, 6, 2, 3, 4, 1] [Monday, ditto: 4, 2, 9, 11, 3, 5, 10, 6, 7, 8, 1] [Tuesday, ditto: 3, 2, 4, 5, 1, 7, 9, 10, 11, 8, 6]


Lanes

Explanation:
xkcd is a webcomic of romance , sarcasm , math , and language : humor isn't necessarily guaranteed. This comic is an example of that, it being severely depressing.
The comic is built around a dialogue between two people (we'll say Cueball is the one talking, and the other is his friend) about cancer, presumably cancer that Megan has been diagnosed with. The conversation itself is about as straightforward as a conversation can be. It details the maturation of Cueball 's and Megan 's understanding of cancer diagnoses, knowledge which we can presume he has gained, reluctantly, by watching a loved one suffer.
This whole cancer series was sparked because Randall 's then-fiancee, now wife, is currently in Megan's position, and we, the readers, are now the beneficiaries of this new understanding of cancer diagnoses without having to watch somebody close to us suffer.
The comic's title, Lanes, comes from the two panels which illustrate both ends of the spectrum of Cueball's mental representation of how cancer treatment proceeds. In that there are many possible outcomes for cancer treatment, the image of a multi-lane freeway seems an apt metaphor to represent this understanding visually.
In the first freeway diagram, there are several paths, but the system is very simple, and easy to take in. Only a few lanes lead off into the oblivion which surrounds the freeway, a single off-ramp circles back from the path to survival to treatment, and survival is a visible endpoint.
In the second freeway diagram, however, things are much, much more complex, and much more bleak. Even six years out, survival isn't visible, and many lanes end in oblivion, sometimes not veering off for years after treatment. The title text informs us that this is meant to be loosely representative of breast cancer stages one through four, proceeding by quarters from left to right. It's a grim outlook, hence the friend's understated but completely fitting reaction to this plethora of new knowledge.
Specific numbers:
There are 52 lanes, so 13 lanes per cancer stage. Stage 1 has a 1:12 = ~8% chance of recurrence leading to death within 6 years. Stage 2 has a 5:8 = ~38% chance. Stage 3 has an 8:5 = ~62% chance. Stage 4 has an 11:2 = ~85% chance of death within 6 years.
The opening line of "being in the woods" is revisited in 1928: Seven Years , where Cueball and Megan are shown walking through a forest in a cancer-themed strip.
[The panels are arranged top to bottom. The first is set above a larger image.] Friend: So, are you guys out of the woods? Cueball: We don't know. Friend: Well, did the treatment work? Cueball: We don't know.
[Cueball's next few lines are set by themselves in their own panels, arranged around a larger image.] Cueball: I always assumed that when you got cancer, they gave you a prognosis, then treated you, and at the end of treatment either you beat it or you died.
[The diagram shows a simple highway. Starting at the bottom, with diagnosis for five lanes, the road travels through a cloud of treatment, after which two lanes disappear, and three continue. Later on, there's another off-ramp labeled 'cancer "comes back"', which loops back into the treatment cloud. Otherwise, the highway enters a later cloud called survive.]
Cueball: And I knew sometimes it "recurred," which I assumed meant back to square one. Cueball: But that's turned out not to be quite right.
[Back to Cueball and his friend.] Cueball: Once most cancers spread out into your body, they're incurable. Cueball: If your 10-year prognosis is 60%, that means a 40% chance that some cancer will slip past the treatment and get out.
[The frame zooms in to show just Cueball.] Cueball: So they kill all the cancer they can find, and then you're a "survivor." But your odds are still 60%.
[The panel zooms in further, now showing only Cueball's top half.] Cueball: They can't scan for individual cancer cells. The only way to know if it worked is to wait for tumors to pop up elsewhere. Cueball: If you go enough years without that happening then you were in the 60%.
[The frame shows both people again.] Cueball: And often the first sign is a cough or bone pain. Cueball: So you spend the next five or ten years trying not to worry that every ache and pain is the answer to the question "Do I make it?"
[There's an extra large panel, with a small one floating inside it.] [The panel shows fifty-two lanes emerging from the cloud of 'Treatment'. Signs show 1 year, 2 years, 3 years, 4 years, 5 years, 6 years. Lanes branch off and fade into darkness earlier on the right, with some lanes continuing off the top of the panel.]
[Inset panel.] Friend: Man. Friend: Fuck cancer. Cueball: Seriously.


CIA

Explanation:
Blondie as a news anchor is reporting on a hacker attack on the CIA (hence the title).
This comic is a reference to the attacks by a group briefly known as LulzSec , which was a splinter group from the internet community known as Anonymous , also featured in 834: Wikileaks . In the back of the news report in frame one is the logo that was used by LulzSec. The group was able to publicize several high profile attacks. They were able to briefly take down the CIA website using a DDoS attack. DDoS stands for Distributed Denial of Service in which the attacker uses many computers to send traffic to a host and render it incapable of answering requests from any other computer, effectively taking the site down.
This comic is pointing out the difference between what lay-people ( Ponytail ) and the computer expert ( Megan ) hear when seeing a story like this. Most people may think there is no boundary between the CIA website and its internal network, and conclude hackers compromised the USA intelligence service's most precious data, which would be an incredible display of incompetence by the CIA and would have some pretty obvious negative side effects for CIA assets around the world.
Computer experts, on the other hand, may compare the CIA website to a company's poster, so the damage done is much different and less harmful: the CIA's public relation capacities are hindered for a few hours. The damage from a DDoS is less a catastrophic compromise of valuable federal databases, and more like flash mob crowding in the lobby of the CIA offices, making life mildly inconvenient.
The title text is a transcript of a made up news report. A story similar to the attack is illustrated using old technology. This attempts to demonstrate how silly the news coverage of the real event is. The recruiting poster refers to the CIA website, as it is a PR tool with no connection to sensitive information. It being ten feet high refers to the fact that that the website is open to the public and has limited protections (as danger from a compromised site is low). The ladder technology refers to the DDoS attack, as these attacks are primitive, but possibly well coordinated. The plexiglass poster covers refer to website security tools that may be added to deter future vandalism.
[A television is showing Blondie as a news anchor. The inset picture of the news shows the logo of LulzSec, a man wearing a monocle and top hat.] Blondie: Hackers briefly took down the website of the CIA yesterday...
[Ponytail, sitting in an armchair, is watching a television  (seen from the side) standing on a table hearing what Blondie says as indicated with a zigzag line from the TV. Above the top part of the frame is a smaller frame with a label:] What people hear: Blondie (not shown from the TV): Someone hacked into the computers of the CIA!!
[Megan, sitting in an armchair, is watching a television (seen from the side) standing on a table hearing what Blondie says as indicated with a zigzag line from the TV. Above the top part of the frame is a smaller frame with a label:] What computer experts hear: Blondie (not shown from the TV): Someone tore down a poster hung up by the CIA!!


Tattoo

Explanation:
An oncologist is a doctor who specializes in the treatment of cancer . This comic is certainly related to Randall's wife's breast cancer . Megan in this comic has a tattoo for the alignment lasers of the radiotherapy machine which will fire a beam of radiation with sufficient intensity to kill the cells in the targeted area. A common such machine is a linear accelerator or "Linac" which accelerates electrons to very high speed, these can then either be used to generate high energy X-rays to treat the patient, or the electron beam itself can be used (both are types of radiation; the electrons being beta radiation and x-rays being EM [electromagnetic] radiation). Commonly when radiotherapy is used as part of breast cancer treatment some combination of both is prescribed. In order to allow healthy tissue to recover better, rather than deliver all the radiation in one go, the treatment is delivered a little bit each day over the course of about a month. It is therefore vital that the radiation can be delivered to the correct target area day after day, and this is done by lining up the alignment lasers of the linac with the skin markers - that is Megan's tattoo dots. It may not be considered a "traditional" tattoo (because she says it was done by her oncologist and not in a tattoo parlor).
In the last frame, it is mentioned that Cueball has a barbed wire bicep tattoo, which is common in the US as a tattoo that people get when they want to seem tough, even if they aren't tough already.
The joke in the comic is that Cueball got this barbed wire tattoo to look tough, but it pales in comparison to the tattoo from (or for) the cancer removal or treatment. It is kind of funny because Cueball has his whole shirt off just to show a biceps tattoo.
The title text references gamma ray therapy after describing electron linear accelerator-based treatment systems; however, technically gamma ray therapy only refers to radionuclide (i.e., Cobalt-60) based radiation therapy systems.  In regards to a 90-second session killing a horse, typical dose rates of modern radiation therapy systems are of the order of several gray per minute for the field sizes used, for example, in the treatment of breast cancer .  It is feasible that a single 90-second delivery of radiation could deliver over 10 Gy in a single instance to the specific areas of the body that could be fatal, such as neuropathy or radiation induced liver disease.
[Megan is in the panel. Megan points at her chest.] Megan: I just have one tattoo - it's six dots on my chest, done by my oncologist.
Megan: I need them for aligning the laser sights on a flesh-searing relativistic particle cannon,
Megan: So it will only kill the parts of me
[Dramatic zoom, the panel background is black, with white text.] Megan: That are holding me back.
[The panel is larger, revealing who they're talking to.] Megan: But your barbed wire bicep tattoo is pretty hardcore, too! Cueball: No, it's OK.  I'll just go put a shirt on.


Mac/PC

Explanation:
This comic is a parody of the " Get a Mac " (also known as "I'm a Mac" or "Mac vs. PC") ad campaign for the Mac brand of computers. The ads personified the Mac and their competitors, the PC. The ads poked fun at the PC's terrible function while paying attention to the Mac's unique features. Each ad started with the duo introducing themselves as "I'm a Mac..." "...and I'm a PC."
The comic, however, presents the differences between them as no longer of much importance, since most everything nowadays is done through browsers. In essence, using the same browser to visit the same website among different operating systems would give you an experience that is very much the same. Additionally, there is some self-referential humor here; both the Mac and PC are simple stick figures due to xkcd's style. Therefore, they are literally identical as far as appearance goes. The apotheosis of computing via a browser is probably the Chromebook , a range of laptops whose operating system is based upon the browser Google Chrome , and which first became commercially available a few weeks before this comic appeared.
The title text refers to window management , which is software that controls windows on computers, and is in many ways similar to the more recent development of tabbed browsers. xmonad is one such program, and Randall says that eventually it will be an extension usable with the browser Firefox . What makes it somewhat unusual (and thus worth mentioning) is that it is a tiling window manager , meaning it automatically arranges and resizes newly opened program windows to fit a grid. This is especially useful on large screens.
[Two Cueballs stand facing out of the screen.] Cueball #1: I'm a Mac Cueball #2: And I'm a PC. Cueballs: And since you do everything through a browser now, we're pretty indistinguishable.


Missed Connections

Explanation:
Missed Connections is a page on Craigslist in which people who saw each other briefly and want to reconnect attempt to find each other again. In the case of missed connections, one person describes themselves "Me" and describes the other person "You" in order that the second person would recognize themself and try to reconnect.
The first entry appears to be a goofy joke, although there have been many Wienermobile incidents in the past.
The second entry refers to a person (you) looking down into a wishing well (presumably to throw in a coin to get a wish), but someone (me) is sitting down in the well with a harpoon looking up spotting the silhouette at the top of the well. This seems like a very weird thing to do, and the vaguely human shadow may be lucky to be alive, since the only reason the "you" should know about the "me" is if the me fired the harpoon (and missed). A person sitting in a well telling people stuff (as if it was the well speaking) was the pun in 568: Well 2 . Oddly enough, this entry could possibly be a reference to this episode of The Fairly OddParents .
The third entry is a reference to networking. UDP stands for User Datagram Protocol . UDP packets don't use handshaking to verify they have contacted the correct host, so they can get lost or confused. The Cisco router location is a block of IP addresses that was unallocated at the time when this comic was published but has been allocated to Latin America and Caribbean since then. Cisco is a company that makes networking equipment. This is a play on a missed connection for someone who was lost and asked for directions.
The fourth entry is a reference to two events in 2011 in which President Barack Obama invited rappers--among other people--to the White House. After each event, right-wing commentators blasted the event as a party unbecoming of the dignity of the White House. Nancy Pelosi is the Democratic Leader of the US House of Representatives . The acronym (D-CA) is a common notation for politicians which notates party (D for Democrat) and state (CA for California). Pelosi would have also been invited to these events, and the missed connections listing is a reference to what the commentators imagined the event would have been like. A " juggalo " is a term referring to a fan of the rap group Insane Clown Posse (which includes rapper Violent J ), which is notorious for having a wild, misogynistic, and violent fanbase.
The fifth entry is a straightforward joke. One of the two people getting married was so distracted by their phone they have no clue where their spouse is now, or even who they are. Alternatively, it could be that the second party deserted the wedding because they were frustrated by their partner being distracted by their cell phone during the wedding, and the first partner is now hoping to convince them to return.
The sixth entry is a reference to how the Google Street View car was not only recording photos of the street in 360 degrees, it was also collecting data from unencrypted Wi-Fi networks. The comic takes this to the next level, that the Google Street View van also scans what we have in our pockets and does a retinal scan. In this case, the social security number referenced is the most used SSN of all time. The retinal scan takes this even further, indicating that Google's cameras are collecting fine enough images to identify people by Retinal scan .
The entry gets a bit absurd when you realize with all this data, it should be trivial for the Google employee to ID and meet this young man, and would not need the Missed Connections page.
The last entry suggests that Babe Ruth , the American baseball slugger of 1914-1935, is actually a Time Lord . Time Lord is a reference to the popular sci-fi series Doctor Who in which The Doctor, who is a Time Lord, uses a TARDIS , which is a time travel machine. Possibly because he was a baseball player "ahead of his time".
The title text is another reference to the privacy concerns surrounding Google Street View van, to which Google responded by claiming that the street view camera wouldn't capture anything that someone walking by wouldn't be able to see. Randall is not worried about the street view van since he expects that Google will already know anything that such a van could discover from reading his e-mails. This last statement is of course much more serious than having a photo taken by a passing van, thus making it clear what people should fuss about, and it is not the van.
[The page is set up like the missed connections area of Craigslist, with a list of messages from an individual to a person they weren't able to communicate with at the time. All readable text is in blue. There is a large heading at the top:] Personals > Missed Connections
[Below the heading there is a gray section in a black frame with two lines. The first line has a search box and a  drop down menu with text and two black arrows to the right of it. The second line has three check boxes and two other boxes, all empty. all boxes has white background. Text is written many places around these boxes (and on the drop down menu), it is written in black, but none of it is readable.]
[Below this gray section follows seven missed connections, the last being cut before the description of "Me" is finished, and the line visible is cut of, so the lower third of the letters are hidden below the comics frame.]

You: Clinging to hood of your stolen Wienermobile, trying to reach into engine to unstick throttle Me: Screaming, diving out of the way
You: Vaguely human silhouette Me: At bottom of wishing well with harpoon gun
You: Confused UDP packet Me: Cisco router in 45.170/16 block
You: Baddest fuckin' Juggalo at Violent J's party Me: Nancy Pelosi (D-Ca)
You: Getting married to me Me: Also getting married, but distracted by my phone
You: Cute boy on corner of 4th & Main, 5'11, 169lbs, social security number 078-05-1120, pockets contained $2.09 in change, keys, and a condom. Retinal scan attached Me: Driving street view van
You: George Herman "Babe" Ruth Me: Fellow Time Lord. Saw your Tardis on third moon of


Password Strength

Explanation:
This comic says that a password such as "Tr0ub4dor&3" is bad because it is easy for password cracking software and hard for humans to remember, leading to insecure practices like writing the password down on a post-it attached to the monitor. On the other hand, a password such as "correct horse battery staple" is hard for computers to guess due to having more entropy but quite easy for humans to remember.
Entropy is a measure of "uncertainty" in an outcome. In this context, it can be thought of as a value representing how unpredictable the next character of a password is. It is calculated as log2(a^b) where a is the number of allowed symbols and b is its length.
A truly random string of length 11 (not like "Tr0ub4dor&3", but more like "J4I/tyJ&Acy") has log2(94^11) = 72.1 bits, with 94 being the total number of letters, numbers, and symbols one can choose. However the comic shows that "Tr0ub4dor&3" has only 28 bits of entropy. This is because the password follows a simple pattern of a dictionary word + a couple extra numbers or symbols, hence the entropy calculation is more appropriately expressed with log2(65000*94*94), with 65000 representing a rough estimate of all dictionary words people are likely to choose. (For related info, see https://what-if.xkcd.com/34/ ).
Another way of selecting a password is to have 2048 "symbols" (common words) and select only 4 of those symbols. log2(2048^4) = 44 bits, much better than 28. Using such symbols was again visited in one of the tips in 1820: Security Advice .
It is absolutely true that people make passwords hard to remember because they think they are "safer", and it is certainly true that length, all other things being equal, tends to make for very strong passwords and this can be confirmed by using rumkin.com's password strength checker . Even if the individual characters are all limited to [a-z], the exponent implied in "we added another lowercase character, so multiply by 26 again" tends to dominate the results.
In addition to being easier to remember, long strings of lowercase characters are also easier to type on smartphones and soft keyboards .
xkcd's password generation scheme requires the user to have a list of 2048 common words (log 2 (2048) = 11). For any attack we must assume that the attacker knows our password generation algorithm, but not the exact password. In this case the attacker knows the 2048 words, and knows that we selected 4 words, but not which words. The number of combinations of 4 words from this list of words is (2 11 ) 4 = 2 44 , i.e. 44 bits. For comparison, the entropy offered by Diceware's 7776 word list is 13 bits per word . If the attacker doesn't know the algorithm used, and only knows that lowercase letters are selected, the "common words" password would take even longer to crack than depicted. 25 random lowercase characters would have 117 bits of entropy , vs 44 bits for the common words list.
Example
Below there is a detailed example which shows how different rules of complexity work to generate a password with supposed 44 bits of entropy. The examples of expected passwords were generated in random.org.(*)
If n is the number of symbols and L is the length of the password, then L = 44 / log 2 (n).
a = lowercase letters A = uppercase letters 9 = digits & = the 32 special characters in an American keyboard; Randall assumes only the 16 most common characters are used in practice (4 bits)
(*) The use of random.org explains why jAwwBYne has two consecutive w's, why Re-:aRo has two R's, why [email protected] ~"#^.2 has no letters, why ewpltiayq has no numbers, why "constant yield" is part of a password, etc. A human would have attempted at passwords that looked random.
The title text likely refers to the fact that this comic could cause people who understand information theory and agree with the message of the comic to get into an infuriating argument with people who do not — and disagree with the comic.
If you're confused, don't worry; you're in good company; even security "experts" don't understand the comic:
Sigh. 🤦♂
The comic illustrates the relative strength of passwords assuming basic knowledge of the system used to generate them. A set of boxes is used to indicate how many bits of entropy a section of the password provides. The comic is laid out with 6 panels arranged in a 3x2 grid. On each row, the first panel explains the breakdown of a password, the second panel shows how long it would take for a computer to guess, and the third panel provides an example scene showing someone trying to remember the password.
[The password "Tr0ub4dor&3" is shown in the center of the panel. A line from each annotation indicates the word section the comment applies to.]
Uncommon (non-gibberish) base word [Highlighting the base word - 16 bits of entropy.] Caps? [Highlighting the first letter - 1 bit of entropy.] Common Substitutions [Highlighting the letters 'a' (substituted by '4') and both 'o's (the first of which is substituted by '0') - 3 bits of entropy.] Punctuation [Highlighting the symbol appended to the word - 4 bits of entropy.] Numeral [Highlighting the number appended to the word - 3 bits of entropy.] Order unknown [Highlighting the appended characters - 1 bit of entropy.] (You can add a few more bits to account for the fact that this is only one of a few common formats.)
~28 bits of entropy 2 28 = 3 days at 1000 guesses/sec (Plausible attack on a weak remote web service. Yes, cracking a stolen hash is faster, but it's not what the average user should worry about.) Difficulty to guess: Easy
[Cueball stands scratching his head trying to remember the password.] Cueball: Was it trombone? No, Troubador. And one of the O's was a zero? Cueball: And there was some symbol... Difficulty to remember: Hard
[The passphrase "correct horse battery staple" is shown in the center of the panel.] Four random common words {Each word has 11 bits of entropy.}
~52 bits of entropy 2 44 = 550 years at 1000 guesses/sec Difficulty to guess: Hard
[Cueball is thinking, in his thought bubble a horse is standing to one side talking to an off-screen observer. An arrow points to a staple attached to the side of a battery.] Horse: That's a battery staple. Observer: Correct! Difficulty to remember: You've already memorized it
Through 20 years of effort, we've successfully trained everyone to use passwords that are hard for humans to remember, but easy for computers to guess.


TornadoGuard

Explanation:
This is a comic with a take on an application store - the most common app stores are for iPhones and Android devices. App stores take all the reviews and average the ratings for the overall star rating.
In this comic, we see why this is sometimes a bad idea, especially with something as important as an app called TornadoGuard that should alert the user if there is a tornado warning for an area, an announcement indicating that a tornado is approaching. In this case, there are three 5 star reviews about the stability and user interface features of the app, left by users who actually never experienced its core functionality (simply because they never used it in a place where there was a tornado since they got it); however, the only review related to whether the app really works is given the same weight as the others, and sadly for that user, the TornadoGuard app failed in alerting the user to an upcoming tornado. Tornadoes are a recurring subject on xkcd. Also see future comic 1098: Star Ratings , 1754: Tornado Safety Tips .
In 2615: Welcome Back Cueball returns to the app after almost 11 years to find that he has to walk through all kinds of info before getting to know if the visible tornado is likely to head his way...
The title text is software-developer humor, the same as used in 583: CNR which contains further explanation. It is a note from the developer's bug report , which said they could not reproduce the error. Of course, they could only reproduce such a failure if there were a tornado coming towards their area, and if a tornado warning was issued. This is a fairly rare situation, especially in certain areas of the world. This lack of suitable testing conditions explains why the actual alert portion of their code appears to be faulty.
This is a common problem with code that cannot be easily tested -- that when finally needed, it does not actually work.  This is the reason for emergency drills.
In 2219: Earthquake Early Warnings an app for warning of Earthquakes was the main topic, but tornado warnings was mentioned in the title text.
In 2236: Is it Christmas? being right most of the time, except when it matters was the topic.
[The comic is a single panel which resembles a reviews page for a mobile phone application. Next to the app title is a pictogram of a tornado touching the ground]
----App store---- TornadoGuard From DroidCoder2187 ----------------- Plays a loud alert sound when there is a tornado warning for your area. ----------------- Rating: ★★★★☆ Based on 4 reviews ----------------- User Reviews: [The first three reviews show five black stars. The last review shows one black and four white stars.] Reviewer 1 (Dark silhouette): ★★★★★ Good UI! Many alert choices. Reviewer 2 (Helicopter without rotors): ★★★★★ Running great, no crashes Reviewer 3 (White square with black triangles at the top left and bottom right corner): ★★★★★ I like how you can set multiple locations Reviewer 4 (White car): ★☆☆☆☆ App did not warn me about tornado.
[Caption below the comic:] The problem with averaging star ratings


T-Cells

Explanation:
This is a cancer- and leukemia-related comic. Two characters are having a discussion about a new trial ( Porter et al. NEJM 2011 ) in cancer treatment. A trial is done to test a proposed treatment on a select group of patients before approval for the wider patient group.
In this case, the two characters are talking about a trial in which immune cells are taken out of the patient's body and genetically modified. The modified cells are able to both attack the cancer cells and replicate very quickly. However, to make these genetic changes inside the cells, they used HIV as the vehicle to introduce these new genes as it is specialized in invading and modifying immune cells.  HIV is good for this because HIV attacks your T-cells and slowly kills off your immune system. If HIV was used as a vector to introduce a trait into your T-cells it could express a trait to hunt tumors and since it is already good at changing your T-cells it would be well-suited to this task.
Basically, this treatment seems to replace one terrible disease with another terrible disease. As the title text says, they don't know how to get rid of the modified T-cells after they remove the cancer. And the last part of the title text is a joke, in which the doctor suggests yet another disease, smallpox , to inject into the patient's body.  This is similar to the song There Was an Old Lady Who Swallowed a Fly in which a little old lady who swallowed a fly where each time she puts some other animal in her body to get rid of the last one and eventually she dies.  This is akin to that as you have cancer so you put super-strong T-cells modified by HIV to get rid of them but then you have Leukocytosis so you get smallpox to kill those, and so on.
Cueball possibly could have guessed this because he is familiar with biology according to this comic and one of the most common diseases that attacks T-cells would be HIV.
Although highly expensive (because it currently requires customized set of alterations for each individual cancer), over the next few years subsequent clinical trials revealed the power of these super-strong T-cells (called Chimeric Antigen Receptor T-cells, or CAR T-cells for short) to cure previously uncurable cancers.  For example, in 75 children with previously untreatable leukemia, 4 in 5 had no detectable cancer three months after treatment with CAR T-cells ( Maude et al. NEJM 2013 ). More and more different kinds of CAR T-cells are becoming FDA approved to treat a growing number of cancers. Seven years after this cartoon, the American Society of Clinical Oncology chose CAR T-cells as the 2018 Advance of the Year .
[Two people are standing facing each other, having a conversation. One is holding a laptop.] Cueball (with laptop): What's the deal with this leukemia trial? {{Citation: Nejm, Aug 10, 2011}} Friend: Gotta wait and see. Friend: Helping the immune system attack tumors has been a longtime research target. Friend: Lots of promising leads. Often they don't pan out.
Cueball: What'd these guys do? Friend: They took some of the patient's T-cells and patched their genes so they'd attack the cancer. That hasn't been enough in the past but their patch also added code to get the T-cells to replicate wildly and persist in the body.
Cueball: Which worked, but created its own set of problems? Friend: How'd you guess? But I think the craziest part is the way they insert the patched genes. Cueball: How? Friend: Well, think - What specializes in invading and modifying T-cells? Cueball: Seriously? Friend: Yup. Must've been a fun conversation.
[The last panel is set in a doctors office. A patient is sitting on the observation bed talking to their doctor.] Patient: Ok, so I have blood cells growing out of control, so you're going to give me different blood cells that also grow out of control? Doctor: Yes, but it's ok, because we've treated this blood with HIV! Patient: Are you sure you're a doctor? Doctor: Almost definitely.


Arrow

Explanation:
The comic appears to be a reference to 475: Further Boomerang Difficulties , which was a sequel to 445: I Am Not Good with Boomerangs , which had a man throwing a boomerang that never returned. Cueball shoots an arrow off with a bow and a boomerang returns to him. This confounds him. As it was also a Cueball that threw the boomerang in the other comic, this may be the same Cueball that now finally has his boomerang return to him after a long time (464 comics later). This would really freak him out then.
The title text is a pun on how boomerangs always come back, along with how "The Return of X" is often used for movie names.
However, as shown in the prequel as well as in an even earlier comic, Cueball/ Randall has to admit: I Am Not Good with Boomerangs . So for him it would be a surprise if the boomerang returned!
Boomerangs also became a main theme in the interactive comic 1350: Lorenz .
[Cueball stands with a bow and arrow drawn tightly, aiming off-screen.] [He fires the arrow, it disappears offscreen. The bowstring vibrates for effect.] [He stands holding the bow by their side, watching the arrow fly away.] [A boomerang flies on-screen, coming from the direction the arrow was fired. Cueball reaches up to catch the boomerang.] [Cueball is now holding the boomerang, staring at it with confusion.]


Oversight

Explanation:
Fitocracy is a web site that turns workouts into a social game by awarding points, badges, levels and all sorts of other gamification . Megan and Cueball , by their judgment, have spent approximately two hours engaged in sexual activity . However, according to this cartoon, Fitocracy does not consider sex to be an activity acceptable for its site, despite the vigorous nature of Cueball and Megan's sexual workout. This could be due to an oversight (an unintentional error), as the comic is titled, or intentional, as Fitocracy does not consider sex to be an acceptable exercise.
The title text explains how sites like Fitocracy are so successful. Because human brains, especially the cynical ones, like to game the system whenever they can, they will find easy things to do that also score high. In the case of Fitocracy, these are simple exercises that add up a lot when applied daily. But the creators of Fitocracy (and other such successful sites, like Weight Watchers or Lumosity) know this, and, as "in Soviet Russia" , the system games you, as shown, to adopt an exercise regimen, or to lose weight, or to get smarter, or whatever else there is.
Sex does raise your breathing rate and heartbeat, but as sparkpeople (a similar site to fitocracy) notes , it is not as effective as a session at a gym, as it does not typically use the main muscle groups in their full range of motion and doesn't sustain a raised heartbeat for a sufficient length of time. They consider sex to be less effective as cardio than brisk walking, as it burns only about 100-200 cal per hour, which is little raised above a typical resting rate of about 60 cal per hour. (Of course, these statistics exclude several of the sexual activities Megan and Cueball engage in.)
[Megan and Cueball have sex up against a wall.]
[Megan and Cueball have sex standing in an armchair.]
[Megan and Cueball have sex in a swing, swaying above a table with a flower vase on it.]
[Fitocracy. The search phrase is "sex" and the site returned "activity not found."]
[Megan and Cueball stand in front of the computer, Megan is at the keyboard, Cueball stands back wearing a towel tied around his waist.] Megan: Come on! That was like two hours of cardio! Cueball: Hmm, let's see... The part on the dresser was kind of like skiing...


Depth Perception

Explanation:
This comic is one of those that is less focused on humour and more focused on a sense of wonder at the world for both Cueball / Randall and the reader.
Cueball discusses how difficult it is to intuitively feel the reality of how vast the things he sees every day and night are - how big the clouds are, and how far away the stars are. Depth perception - seeing things in 3-D rather than as a flat 2-D image - is partly created by having "binocular vision", or two eyes spaced apart. Each eye sees a slightly different angle on a scene, and the brain combines these two views to give a genuinely three-dimensional view of something. 3-D glasses work the same way, by feeding a slightly offset image into each eye. When you look at far away objects, the offset from each eye is undetectable, and so they may look more like flat 2-D images - hence the impression Cueball has of stars being painted onto a dome rather than being extremely large, far away objects at very different distances.
He wonders if he can work around this impression as far as the clouds are concerned. Normally, Cueball's eyes are a few centimetres apart, like everyone else's, and his 3-D perspective is based on that scale. Here, Cueball puts HD webcams on the tops of football uprights, which are 360 feet (~110 m) apart instead of a few centimetres. He uses strong reading glasses to hold up a smartphone, and feeds the far more offset images of the webcam feeds to each eye so that his brain will create a 3-D perspective of the clouds, which would normally be too massive for the offset between two human eyes to grasp their three-dimensional structure in the same way as smaller, closer things.
This technique doesn't give him the view as if he were a giant as in the final panel, but rather as if he were a giant "at the bottom of an abyss" as per the second-last panel, as the clouds are higher than the goalposts on which the cameras are mounted. The final panel is some artistic license to give the reader a real sense of what it feels like for Cueball to carry this out; it shows us that he has finally achieved a more truthful perspective on the size and shapes of the clouds than he had when he started.
The reason for the reversal of the "right camera" and "left camera" panes on the smartphone screen is unclear, this is likely just a mistake.
The title text is a line from the 1969 song " Both Sides Now " by Joni Mitchell; the full chorus runs: "I've looked at clouds from both sides now / From up and down and still somehow / It's cloud illusions I recall / I really don't know clouds at all." Binocular depth perception involves seeing the same object from slightly different angles, from 'both sides', so Randall is taking the song lyric and literalising it. The song itself has a bittersweet tone and relates to how you understand things differently as you mature, but still don't necessarily feel like you understand them at all, so the tone also fits pretty un-ironically into the theme of the comic.
[The entire comic is narrated by Cueball, and never spoken by the Cueball shown in the examples. All dialog is shown in rectangular frames overlaid on the comic panels.]
[In the first panel the background shows a cloudy sky in color, with the clouds all running together and appearing as a blue gray smear. Towards the bottom the horizon and the ground appear dark almost black at the very bottom. Two frames with two lines of text are at the top left and right, similar below except the one to the left has four lines and the one to the right only one line.] I've always had trouble with the size of clouds. I know they're huge. I can see their shapes. But I don't really see them as objects on the same scale as trees and buildings. They're a backdrop.
[The next panel is split in three parts. The top part is in a single frame. The middle part is frame-less and only has text - the only narrating not inside one of the frames. Then at the bottom there are two frames overlaid over three small panels in a row]
[In the top part of the 2ns panel stands Cueball on a flat disk inside a hemispherical dome with the front half cut away. The dome is about three times as tall as Cueball. Above the dome there is one frame with text. There is also two labeled arrows pointing to the dome and the disk.] Stars are the same way. Arrow up: Sky Arrow down: Ground
[Text in between the top and the bottom panels:] I know they're scattered through and endless ocean, but my gut insists they're a painting on a domed ceiling.
[The next two frames with text is overlaid above (three lines of text) and below (one line of text) the three panels described first. Those three panels are all inverted with black background and white Cueball:] [Left panel: Cueball stands on a curved surface, looking up.] [Middle panel: The perspective of the scene shifts, suddenly the surface Cueball is standing on is in the top left of the panel. Cueball is now looking down, leaning back, and waving his arms trying to regain balance. [Right panel: The perspective of the scene returns to normal, Cueball is now semi-crouched, staring at the ground with legs spaced apart to help him balance.] If I try hard enough, I get a glimmer of depth, a dizzying sense of space, But then everything snaps back.
[An American football field is shown with Cueball drawn very small near the middle. Sections at the left tips of each of the goal posts are highlighted and shown as a zoomed view in an insert box. These insert shows the two webcams mounted on the top of the very tip, one for each goal posts. There are two frames with text above the field, the top one most to the left with one line, the second directly below it with two lines, and below the field there is also one frame with one line in it.] So one summer afternoon I set up two HD webcams hundreds of feet apart, Pointed them at the sky,
[The next two frames with two lines of text each are stretched over the two middle panels in this second row of panels:] [The first panel shows a pair of glasses and a smartphone with an attachment designed to clip onto the glasses. The smartphone screen is setup to display two images side by side such that one camera is visible in the left half of the screen, and the other camera is visible in the right half of the screen. There are four arrows pointing to the two items and to each of the two parts of the screen. They all have labels which are between the two lines of text, but here shown below for clarity.] [The next panel shows the completed phone glasses assembly.] And fed one stream to each of my eyes. The parallax expanded my depth perception by a thousand times, Arrow top left: Right camera Arrow top right: Smartphone Arrow bottom left: Very strong reading glasses Arrow bottom right: Left camera
[Cueball stands wearing the phone glasses assembly, one hand held up to the device, staring into the sky. There are two frames one above and one below with two lines of text each:] And I stood in my living room At the bottom of an abyss
[Another colored panel with blue sky and clouds below the top part of the panel from left to right. Cueball is now a giant who stands in the middle of the frame on the shore of a coastline with a small island off the coast, only a step away for him. A city is near his right foot and the tallest skyscraper appears ankle high. A mountain range is behind him with mountains that are also only barely ankle high. A river flows past the mountains and joins another coming from them on it's way down towards the coast. Cueball is standing with his head well above cloud level as clouds swim around him. At the top above and left of his head the last frame with one line of text is located:] Watching mountains drift by.


Juggling

Explanation:
In an attempt to learn to juggle Cueball begins practicing after reading an instruction book. In the third panel, it seems as though he is juggling normally after tossing the balls into their air. However, in a baffling phenomenon the balls he throws into the air seem to stop adhering to the strict laws of physics part of the way through his throw. As can be proven in simple demonstrations things tend to fall toward the largest center of gravity, and items in motion do not completely stop, unless other forces are at play as well. [ citation needed ]
The joke here is partially making fun of the idea that in a comic, the visuals of juggling would be the same as the visuals sitting in place in the air. So at first while reading, we assume Cueball is juggling, until it is revealed he has no control over the position of the balls at all.
Cueball is understandably perplexed, but instead of ascribing the event to some inexplicable supernatural agent, he concludes that the book's juggling instructions were faulty and throws it away. The title text furthers the joke by implying the book too seems to have become caught up in this phenomenon, which might now occur whenever Cueball throws something.
Many things could be taken away from this. Perhaps Cueball is so spectacularly bad at juggling his failure breaks the laws of physics. Or perhaps the book assumes gravity and momentum are present where you choose to juggle. Or perhaps the book merely instructs you how to juggle like the picture on the front of the cover, where the balls can also be thought to hover.
However it seems that for some reason physics has only stopped acting on these objects as Cueball himself is able to jump and fall back down without any trouble and the book was previously on the floor, implying it had been dropped there.
While it is possible to reach zero gravity (or at least microgravity), there is no place in our universe where objects with mass have no momentum. Some possible explanations might be that Cueball is outside of our universe, he has just discovered something that's theoretically impossible, or he is just dreaming, or Randall has taken comedic license on the "momentum" part for the sake of the joke.  Or he could be in a place where the surrounding fluid, instead of having the normal properties of earth's atmosphere, is a very thick or viscous fluid in which things simply become stuck. Or, perhaps the fourth wall is broken, and Cueball doesn’t recognize he’s in a web comic, but we do.
This may also be a reference to a motto often brought up in the Hitchhikers Guide to the Galaxy series: if you forget about physics, they will forget about you.
This comic is part of the following unpublished comic from the five-minute comics ; specifically the unpublished fourth part .
[The panel shows a close up of Cueball reading a book. The book is called "How To Juggle" and has a picture of a person juggling on the cover.]
[The view now shows the entirety of Cueball. The book is splayed on the floor behind them, and he is holding some juggling balls.]
[Cueball throws the juggling balls in the air.]
[He lowers his arms to prepare to catch the balls. The balls are hovering in mid-air.]
[Cueball now stands with his arms by his sides. The balls have not moved and are still suspended in mid-air.]
[Cueball jumps, trying to grab the lowest ball. He can't reach.]
[Cueball scratches his head and stares at the still floating juggling balls.]
[Cueball throws the book into a trash can.]


Empirical

Explanation:
When faced with the question "Will you marry me?", Cueball approaches the question in an empirical way. The word empirical denotes information gained by means of direct observation or experiments. In this comic, Cueball completes the "Will you marry me?" experiment, by actually getting married (as opposed to deciding on the spot or taking time to think) and the results are "yes".
The word "will" has two meanings: auxiliary verb of the future and disposition to do something. In the first sense Cueball cannot answer this question since he cannot know the future. Of course the question Will you marry me? uses the verb will in the second sense.
This comic is likely a reference to Randall 's marriage around this time.
The title text states that Cueball is surprised by the results, suggesting that Cueball actually was not confident of his ability to marry, meaning that perhaps the marriage is not in good standing.
[Two people are standing together, Megan and Cueball.] Megan: Will you marry me?
[Cueball throws his hands in the air excitedly.] Cueball: Let's find out!
[The couple are now standing in front of an altar. A flower arch stretches over the couple and a person is standing behind the altar. Megan is wearing a knee length white dress and a veil. Cueball is wearing a bow tie. They are holding hands.]
[The couple stand together, still dressed from the wedding and still holding hands.] Cueball: Apparently, yes!


Hurricane Names

Explanation:
The World Meteorological Organization (WMO) maintains lists of potential names for tropical cyclones in each tropical cyclone basin ; Regional Specialized Meteorological Centres (RSMCs) and Tropical Cyclone Warning Centres (TCWCs) are responsible for assigning those names to tropical cyclones within their respective areas of responsibility. In the North Atlantic Ocean (including the Gulf of Mexico and Caribbean Sea as pictured), the NOAA 's National Hurricane Center (NHC/RSMC Miami) gives names to tropical cyclones (of which hurricanes are a subset), going through the alphabet (excluding Q, U, X, Y, and Z) and resetting at "A" at the beginning of the year. For example, the North Atlantic storms in 2012 were named "Alberto", "Beryl", "Chris", "Debby", and so on. There are six lists of names for the North Atlantic Ocean, which rotate every six years. Storms that are extremely catastrophic are removed from the lists.
If there were more than 21 hurricanes in a season before 2021, the 21-letter alphabet becomes exhausted and the hurricanes are named with Greek letters. This has happened only twice: in the 2005 Atlantic hurricane season , see 1126: Epsilon and Zeta , and in the 2020 Atlantic hurricane season . In 2021, the World Meteorological Organization ended the use of the Greek alphabet and unveiled a supplementary list of names to be used in event of exhaustion.
There have never been enough cyclones in one season to exhaust both the English and Greek alphabet (which would require more than 45 cyclones in a season; the most so far has been 30), and Randall is hypothesizing what the names would be if this happened. In the comic, the NHC has named the hurricanes using random words out of the Oxford English Dictionary (OED). The humor here is intrinsic: "Hurricane Eggbeater" is a bizarre and hilarious name (and may also refer to how an eggbeater spins and 'destroys' an egg in a similar manner to how a hurricane might affect the surrounding area). The place in the image shown is the Gulf of Mexico and its surroundings, with the land being white, and the ocean, black.
The title text takes this already surreal twist to an even more ridiculous extreme, where an impossibly long hurricane season exceeds 300,000+ storms and exhausts the OED completely.  Even when the NHC starts referring to them using counting numbers , which will be sufficient to cover an infinite number of hurricanes, they are foiled by a theorem in set theory .  In mathematics, the set of all counting numbers is a countable set (as are the set of all integers or all fractions) whereas the set of all points on a surface is an uncountable set (as is the set of all real numbers). Cantor diagonalization is a famous proof that it is impossible to map objects from an uncountable set one-to-one with objects from a countable set.  Applying this theorem to hurricanes, if there were to be one hurricane for every possible point on Earth's surface, it would be impossible to assign a distinct counting number to each one.  This of course defeats NHC's last-resort naming scheme, but more pertinently, human civilization would be in a lot of trouble.
At this point, the meteorologists give up and decide to name all the hurricanes "Steve", which is popular on the internet as an arbitrary, generic name. Ironically, this makes "Steve" no longer arbitrary. The reporter then goes on to tell people that their forecast is "Steve" meaning that the hurricanes are everywhere. He says "good luck", which is probably because there are currently hurricanes on all points of the earth's surface at the time of his speaking.
[A weather reporter sits behind a desk with an image of the Gulf of Mexico and surrounding land masses displayed to his left. 9 hurricane symbols are scattered across the map, primarily over Cuba.] Reporter: After the latest wave of hurricanes, not only have we run through the year's list of 21 names, but we've also used up the backup list of Greek letters. All subsequent storms will be named using random dictionary words. Reporter: The newly-formed system in the gulf has been designated "Hurricane Eggbeater", and we once again pray this is the final storm of this horrible, horrible season.


I'm Sorry

Explanation:
The term "I'm sorry" expresses a general feeling of sorrow or grief. It can be used either as an apology (expressing sorrow for one's own actions) or of sympathy (expressing sorrow for someone else's misfortune). Both uses are normal and acceptable, and the distinction is generally clear from the context. Some people deliberately conflate the two uses, treating an expression of sympathy as if it were an apology. This confusion is almost always feigned, as both uses of the term are well understood.
As it says below the comic, when Megan rejects his sympathetic "I'm sorry" by treating it as if it were an apology and saying it was not his fault, rather than just agreeing with her, an irritated Cueball implies that it was always intended as an apology, because he DID, in fact, burn down her mother's house. It is unlikely that he actually burned her house down, but rather is simply teaching Megan a lesson not to nitpick so much.
The title text has Cueball further attempting to convince Megan that he is not just being sarcastic, but really did set the fire, for the simple reason that he hates her mother.
[Megan and Cueball are standing next to each other having a conversation.] Megan: My Mom's house burned down. Cueball: Oh! I'm sorry! Megan: Why? It's not your fault. Cueball: It's nice of you to say that, but I know what I did.
[Caption below the panel:] It annoys me when people interpret an obviously sympathetic "I'm sorry" as an apology, so I've started responding by making it one.
This kind of game, in which a deliberate misunderstanding of language is treated as the other person's fault seems to be a peeve of Randall's, and is dealt with in several other strips, for instance, 169: Words that End in GRY .


Family Decals

Explanation:
There exists a current fashion among car owners to place decals on their back window that represent their family. The decals consist of stick figures to depict the parents and children, perhaps shown doing a favorite activity, and even pets.
The first car window features a couple with three children, while the other shows just a couple ( Cueball and Megan ), with piles of dollar bills and two large bags with dollar signs on them. The humor comes from the opportunity cost implied in this — not having children allows you to avoid the expense of raising them and accumulate money for your own use.
One might expect that the cars would represent the difference in wealth, and they are identified as 'urban SUV' and 'sporty hatch back' in the official transcript . The larger car is a Subaru Outback which is a typical car used by families. The second car is a Honda Fit , which is a budget compact hatchback, in the comic it has a spoiler added. The Subaru Outback is more expensive now than the Honda Fit, which seems to fit perfect with the comic's implication since a family of five have to buy the large expensive hatchback. Being able to buy a smaller car that doesn't need to hold a five member family also allows you to save more money.
The title text refers to the humorous description of cats as the real masters of their household, and the little girls surrounding the cat refers to their ability to influence humans with their cuteness (as referenced in 231: Cat Proximity ). The implication is that any adults in the household have a limited, non-credited role. The title text could also be a reverse of the stereotypical "crazy cat lady". Instead of someone owning a very large quantity of cats it could be one cat with an ungodly number of little girls.
[Close up of the rear ends of two cars parked next to each other. Both have white stickers on their black rear windows. The car on the left is an urban SUV and most of the rear is visible with all the lights and a readable license plate with gray text visible. Its stickers represent a family. From left to right they are a Cueball-like guy, a woman with white hair like Blondie (i.e. black shows through), a girl with two ponytails, a boy of the same height and a smaller boy, both boys Cueball-like. The car on the right is a sporty hatch back, and only the left part until the middle is shown. The left lights and the very left part of the license plate can be seen. Its stickers show Cueball, Megan and then a large pile of dollar notes (six piles of different heights) and two large money bags with dollar signs on them, and the rear left bag is partly hidden by two piles of notes.] License plate of SUV: ICE-LI3 License plate of sporty hatch back: 4[cut off]


Investing

Explanation:
Compound interest is a type of interest in which the interest earned is added to the total amount, so that the interest itself then begins to gain interest in an exponential fashion. This contrasts to simple interest , where the amount used to calculate the interest will always stay at a fixed value. In economics classes, many teachers like to demonstrate extreme examples of compound interest, typically turning a thousand dollars into tens of thousands thanks to unrealistically high interest rates over several decades. But here, Ponytail discovers that a more realistic example is less than overwhelming. Instead of simple interest of 2% earning $200 in ten years, with compounding $219 is produced, hardly any better on a $1000 investment.
There is an urban legend that Einstein said that compounding interest is the most powerful force. Snopes has its doubts about it .
The idea in the title text that people take advice from physicists making small talk is also referenced in 799: Stephen Hawking and 1206: Einstein .
Ponytail: Sure, 2% interest may not seem like a lot. But it's compound !
[Ponytail opens a computer and begins calculating.] Ponytail: If you invest $1,000 now, in just ten short years you'll have... ...let's see...
Ponytail: ...$1,219.
Ponytail: Ok, so compound interest isn't some magical force. Megan: Yeah, I'm just gonna try to make more money.