Making Rules

Explanation:
" Punch Buggy " is a game played by two people with a view of traffic (often, but not here, during a car ride). For each Volkswagen Beetle that passes nearby, the first player to see it is entitled to punch the other player, while calling "Punch Buggy" followed by the colour of the spotted Beetle. Traditionally the other player is permitted to return the punch, unless the first player also calls "no punch back."
Many people will just assume that the game is always being played and punch you out of the blue, giving you no chance to opt out. Cueball , however, finds the idea that he can simply be roped into a game without consent odd, and decides to make the game stakes more desirable than just the right to punch someone, and (seemingly successfully) uses the same principle to secure the right to sleep with the other man's girlfriend.
The title text is Randall elaborating on how ridiculous these types of games are, such as the idea that after being punched, one should just accept a "no punch back" rule.
In the UK, a common variant uses a yellow Mini rather than the VW Beetle. Other examples of this type of game are the Car numberplate game and Padiddle .
[Two men are sitting. A yellow buggy passes by.] Man: Punch buggy yellow no punch back! [Man punches Cueball, Cueball punches the man back, with seemingly greater force, causing the man to fall of the bench they are sitting on.] Man: I said no punch back! Cueball: You can do that? Cueball: Man, this changes everything . Soon... [A blue buggy passes by, and Cueball is holding Megan's hand.] Cueball: Sleep with your girlfriend buggy blue! Man: Hey! Cueball: No complaining back! Man: Aww...


Ultimate Game

Explanation:
Gary Gygax was a game designer best known for co-creating the iconic nerd pastime Dungeons and Dragons (D&D); as such, he is commonly described as the "father of D&D." He died on March 4, 2008, three days before this comic was released. It made him the first person to receive tribute in conjunction with his death on xkcd, but not the last .
The idea of playing games (typically chess) with supernatural entities in exchange for one's soul is an old one and has been referenced in many works , but mainly known in the form of playing Chess against the personified version of Death , which was made famous in Ingmar Bergman's film The Seventh Seal (1957). The last part of this trope is used in this comic. Here, the specific twist is that the victim can choose which game they want to play. Naturally, it is only fitting that Gary would challenge Death to D&D . The trope was later revisited as one of the tips in 1820: Security Advice .
The problem is that Dungeons and Dragons isn't so much a game as it is a set of rules for describing stories. It requires the intervention of a Dungeon Master (or DM) to create a scenario that the players' characters must overcome. It's unclear exactly how the game between Gary and Death works, but given that D&D generally takes a long time to play due to the setup time and large amount of dice-rolling, and the fact that Gary seems to keep adding extra rulebooks (official or pseudo-official books that add new classes, items, spells, etc. for players to use), it's understandable why it would take longer than Death's boss would like.
Part of the humor in this comic comes from the fact that Death's boss, who would presumably be an extraordinarily powerful entity, appears to be a completely ordinary man in an ordinary office, complete with bald patch and potted plant.
Death's usage of the name "Jesus" in the final panel may be considered ironic, given that he's, well, Death. But it does make a different kind of sense when you consider Jesus a personal enemy of Death (Revelation 20:14).
[Split screen down the diagonal. Upper left: A man with only hair around the back of his head is standing to the left of a desk with a hand on it, speaking on an office phone on a desk. There is a photo in a frame behind the phone. Bottom right: Death in a cloak, black hole to the left where the head should be, speaks on cell phone he is holding up in his skeleton hand.] Man: Death? Death: Speaking.
[A frameless panel with a zoom out of the man on the phone, showing more of his office. Behind the desk, there is a potted plant, and above it, there is a window (or a white board). The reply over the phone is indicated to come from the phone with a zigzag line.] Man: This is the boss.  Where are you? You haven't been up to the office in days! Death (over the phone): I've been held up.
[Full panel with Death speaking on his cell phone. It is apparent that he is leaning back against something white behind him (presumably the backrest of his chair). The two replies on the phone are again indicated with zigzag lines.] Man (over the phone): What happened? Death: You know how when someone dies, they can challenge me to a game for their soul? Man (over the phone): Sure, standard procedure.
[Death is revealed to be sitting on a chair to the right of a table leaning back against the chair's backrest (which could be seen in the first two images of Death as well). He is still speaking on his phone, and in the other hand he holds his long scythe down with the blade below the table. On the other side of the table is a man (revealed to be Gary Gygax in the title text).  The man has curly hair that seems to turn into a ponytail, but as he is looking out of the panel a little to the left away from Death, it is hard to see the ponytail. He also has a full beard. Gary Gygax is leaning over his bag behind him, taking out a book while resting the other hand on the table. On the table are already two other books of the same type. Behind them are two figurines (one Cueball and one with a pointy hat), then two dice and some paper strewn about in front of Death.] Death: Well, we didn't count on this guy. I might be a while. Gary Gygax: I add the paladin to my party. Death: Oh, Jesus. He's getting out another rulebook.


Kilobyte

Explanation:
This comic pokes fun at the confusion over the definition of a kilobyte. Historically, 1024 bytes was called a kilobyte for convenience purposes (same with megabyte and gigabyte); this usage was frowned upon by both the International Bureau of Weights and Measures and the Institute of Electrical and Electronics Engineers , but both let it slide as they had more important things to deal with. Later, hard drive manufacturers realized they could save money by selling hard drives marketed X amount of gigabytes and declare that they meant it as a literal 1,000,000 bytes (a 7% difference). Despite its iffy origins, the official definition now states that 1 kilobyte is 1000 bytes, however some continue to use the older meaning referring to 1024. The first row of the table is simply mocking this discrepancy.
The second row is Randall's interpretation on how Stan Kelly-Bootle would approach this problem. Kelly-Bootle is known for writing The Computer Contradictionary , which satirizes the jargon and language of the computer industry. Kelly-Bootle was likely motivated to write this work after working for several years at IBM, a company infamous for its excessive use of acronyms in the work place. Averaging the two definitions together to get 1012 bytes is simply a humorous approach that Kelly-Bootle would likely have taken (" Should array indices start at 0 or 1? My compromise of 0.5 was rejected without, I thought, proper consideration. " — Stan Kelly-Bootle). The serendipitous fact that the initials of Kelly-Bootle's name are "KB," the same letters used to abbreviate the word "kilobyte," adds a layer of plausibility to the joke. This is the first of Randall's many humorous compromises .
The imaginary kilobyte simply plays on the fact that complex analysis is required in quantum computing in relation to quantum mechanics. The imaginary number is represented as i and has a value of the square root of -1. This is a pun on the fact that KiB is used for the "binary kilobyte" (occasionally " kibibyte "), which is standardized at 1024 bytes.
The Intel kilobyte mocks the Pentium floating point unit that, in 1994, became notorious for having a major flaw in its floating point division algorithm that gave slightly erroneous results.
The smaller, drivemaker's kilobyte mocks a business model for handling higher prices that keeps prices constant but reduces quantity. The food industry has been notorious for decreasing quantity of food and keeping prices the same instead of increasing prices and keeping quantity the same. Randall is suggesting that if the computer industry tried to do this with hard drives, it could have humorous results such as smaller number of bytes in a kilobyte. In reality, hard drive capacity is specified in 10 3 byte (kB) units, while the content you put on it (programs, etc.) is specified in 2 10 (KiB) units. Formatting the drive, i.e. making it usable for storage, further decreases the available space. Thus a 250 GB drive might be reported to have a capacity of only 232 GB (really GiB) by the operating system. This discrepancy increases with increasing drive size. The trend humorously suggested in the comic, however, would make the drivemaker's kilobyte 1024 bytes in 1979, 1000 bytes in 1985, 852 bytes in 2022, and 0 bytes in 2235!
The baker's kilobyte is a play on the baker's dozen , which is 13 instead of 12. A baker's byte with 9 bits to the byte would result in a total of 9216 bits in a 1024 byte kilobyte. Converting this into "normal" bytes (with 8 bits), we divide 9216 bits by 8 bits per byte to get 1152 8-bit bytes to the baker's kilobyte.
In the title text, Randall mentions the definition kibibyte , which is defined more precisely. The binary prefix kibi means 1024, a portmanteau of the words kilo and binary. But he doesn't like the word because it sounds like the dog food Kibbles 'n Bits .
There's been a lot of confusion over 1024 vs 1000, kbyte vs kbit, and the capitalization for each. Here, at last, is a single, definitive standard: [table of various kinds of kilobytes]
SYMBOL NAME SIZE NOTES kB Kilobyte 1024 bytes OR 1000 bytes 1000 bytes during leap years, 1024 otherwise KB Kelly-Bootle standard unit 1012 bytes compromise between 1000 and 1024 bytes KiB Imaginary kilobyte 1024 √-1 bytes used in quantum computing kb Intel kilobyte 1023.937528 bytes calculated on Pentium F.P.U. Kb Drivemaker's kilobyte currently 908 bytes shrinks by 4 bytes each year for marketing reasons KBa Baker's kilobyte 1152 bytes 9 bits to the byte since you're such a good customer


Morning

Explanation:
This comic makes reference to the idea, as presented in the movie The Matrix , that reality is a computer simulation. In LCD screens , especially TFT LCD , a dead pixel is a pixel that does not work properly, usually set as black or as some other color. Megan realizes that the reality is a computer simulation when she sees dead pixels in the sky, indicating that what she sees is an LCD screen.
In the last panel of the comic, there are two red and one green pixel that look exactly like actual dead pixels.
The title text refers to usual techniques for fixing a dead pixel. One way is to apply pressure and release it, which isn't possible for Megan due to the distance of the sky. Another way is to make the area of the screen that the dead pixel is on change colors really quickly, which could happen if the day-night cycle was fast enough.
[Megan is standing to one side.] We've all seen The Matrix We've all joked about "What resolution is life" But it doesn't blunt the shock Of waking up one morning [Megan looks up from field and sees several colored pixels in the sky.] And seeing dead pixels in the sky.


The Ring

Explanation:
The Ring is a horror movie released in 2002 based off of the Japanese movie Ringu . In it, there is a video tape that causes everyone who watches it to die after seven days. However, the viewer can prevent their death by making a copy of the tape and giving it to someone else.
A young Cueball watches the tape and prevents his own death by "copying" the tape and uploading it to a video-sharing website, presumably YouTube . Cueball not only got one person to watch it, the requirement for escaping death, but 363,104 people, all of whom are most likely going to die in seven days. (For scale, the most-watched video at the time of the comic's publication had 78 million views.)
Rickrolling is an Internet meme where someone is lured into clicking on a video link of Rick Astley singing " Never Gonna Give You Up ." When someone is rickrolled, they usually get very upset. Cueball states in the comic that he uploaded the tape to get revenge on everyone who rickrolled him, though it was obvious that he would likely kill many more people than those who rickrolled him (or those who've rickrolled anyone else).
The title text refers to the file format used by the YouTube player. Historically, YouTube was famous for having extremely poor quality videos, because their Internet connections were slower and server storage space was expensive. So, all videos were transcoded into a very low quality FLV (flash video) format.
The girl shown in the video tape — a major part of The Ring series — is named Samara. Posting the tape on YouTube would result in heavily compressed videos in the FLV format. This, presumably, would reduce the quality of Samara's apparition. The title text also implies that nobody deserves that, although rickrolling is (according to young Cueball) apparently punishable by death.
[Ponytail is speaking to young Cueball sitting in front of a TV with a black background and a white ring.] Ponytail: You watched the tape!? Cueball: Yeah, sorry.
Ponytail: Now you'll die in seven days! Cueball: It's worse than that.
[TV is cut from the frame.] Ponytail: ...You didn't. Cueball: Yup.
[Both are now in front of a computer, Ponytail leaning in.] Ponytail: Great, it's got 363,104 views already . Cueball: It was only fair. Cueball: They kept Rickrolling me!


Unscientific

Explanation:
In the first and second frames, Megan can be seen accusing MythBusters of not actually "doing science" because of its lack of rigor - a debate beyond the scope of this Wiki. The zombie of deceased physicist, Richard Feynman , comes to explain to Megan that she has failed to recognize the purpose of MythBusters . He explains that MythBusters' value is getting people to accept and understand the importance of experimentation in the scientific method, and that more complex lessons (such as on rigor) would be wasted on people who don't understand those basics.
In the last frame, Cueball attempts to save himself and Megan from zombie Feynman by implying that physicists, being extremely intelligent, would have more desirable brains. Also, in a science lab, the number of brains available would be higher than just two. Feynman's closing remark implies that string theorists have no brains; the joke being that string theorists are presumably less intelligent than Cueball and Megan, who were merely watching television prior to being attacked, and probably also a pun on branes . For another instance of Randall knocking string theorists, see 171: String Theory . This notion fits appropriately with Feynman's description of the core of science. Moreover, Feynman's own career involved applying physics to real world applications (such as for the Manhattan Project), whereas the work of string theorists is theoretical and untested.
The title text starts by rebounding against the complaint of validity as science by purportedly tackling a really big scientific inquiry. Then he veers away into two far more esoteric proposed fields of study, of which at least one is not even determinable by the scientific method, probably both.
The Mythbusters episode being watched is likely Episode 109 – "Ninjas 2" , which was the second episode in which the Mythbusters attempted to catch an arrow mid-flight. The voice from the television is likely that of Robert Lee , who provided the narration for Mythbusters . It should also be noted that the ninja mentioned in this is the inaccurate pop culture iteration not the historical Shinobi no Mono. for more accurate info on the Shinobi search "Antony Cummins" .
Zombies are a recurring theme in xkcd, particularly zombie scientists, which has also occurred twice after this comic with Paul Erdős in 599: Apocalypse and Marie Curie in 896: Marie Curie .
[Cueball and Megan are sitting on a coach, watching Mythbusters.] TV: Can a ninja catch an arrow? On this episode, we'll find out! Cueball: Mmm, science. Megan: Hey, Mythbusters is entertaining, but it's not science.
Zombie Feynman: BRAAAAAIIINNS ... Cueball: Zombie Feynman! Zombie Feynman: You got a problem with Mythbusters? Megan: They fail at basic rigor!
Zombie Feynman: "Ideas are tested by experiment." That is the core of science. Everything else is bookkeeping.
Zombie Feynman: By teaching people to hold their beliefs up to experiment, Mythbusters is doing more to drag humanity out of the unscientific darkness than a thousand lessons in rigor. Show them some love.
Zombie Feynman: Anyway, back to zombie stuff. I hunger for BRAAAAAIIINNS! Cueball: Uh, try the physics lab next door. Zombie Feynman: I said brains . All they've got are string theorists.


Tap That Ass

Explanation:
In this comic, Cueball either accidentally or purposefully exploits the double meanings of "tap." The phrase "tap that ass" is a colloquialism for "to have intercourse with that person" and is most likely how the reader expects the phrase to be used. However, throughout the comic, Cueball uses the phrase ambiguously.
In the first panel, it is possible that Cueball is using "tap that ass" sexually. However, it is more likely that he is using "tap" to mean "pick" or "choose," in which case he would be the one choosing the next committee chair. "That ass" refers to one of the individuals in the meeting room to be picked for the position.
In the second panel, "tap" is referring to wiretapping. The Cueball character with the headphones on has just unplugged his headphone. This suggests that he and his colleague at the phone were just done with the wiretapping. In this scenario, it is strange that the colleague is still on the phone instead of hanging up. However, it would be much stranger to wiretap someone in plain eyesight, unless that person is blind. "Ass" likely refers to the person they have just wiretapped. Cueball says he'd tap that ass "without a warrant," suggesting that they had one in this situation.
In the third panel, "tap" is referring to extracting sap from trees. A sexual connotation would make no sense in this context. "That ass" refers to the maple tree.
The final panel reveals that Cueball was purposefully implying the sexual meaning of "tap that ass" all along, even though he framed it in a non-sexual context. He reaffirms his previous statement from the third panel by turning toward the direction of the third panel (thus implicitly breaking the fourth wall) and asserting "I'd have sex with that tree." "That tree" refers to the tree from the previous panel.
Alternatively, Cueball may have finally realized that he indeed wanted to have sex, but instead of using the euphemism "tap that ass," he says it literally.
The title text features a request from Cueball from the last panel to Cueball from the third panel. He asks Cueball not to plug up the hole left behind from tapping the tree, so he can have sex with it.
[Cueball in a hallway looking in on a board meeting.] Cueball: I'd tap that ass to be the new committee chair. [Cueball wearing headphones with a briefcase and a laptop. Another man on a telephone.] Cueball: I'd tap that ass without a warrant. [Cueball with his hand on his chin, looking at a tree.] Cueball: I'd tap that ass and extract delicious maple syrup. [Cueball standing in a blank frame.] Cueball: I'd have sex with that tree.


Travelling Salesman Problem

Explanation:
The travelling salesman problem is a classic problem in computer science. An intuitive way of stating this problem is that given a list of cities and the distances between pairs of them, the task is to find the shortest possible route that visits each city exactly once and then returns to the origin city. A naïve solution solves the problem in O(n!) time (where n is the size of the list), simply by checking all possible routes, and selecting the shortest one. However, this approach will take a long time as the number of possible routes increases exponentially as more nodes are included.
A more efficient dynamic programming approach yields a solution in O(n 2 2 n ) time. These times are given using Big O notation , which is commonly used in computer science to show the efficiency or complexity of a solution or algorithm.
The joke is that the salesman selling online (say on eBay , Amazon Marketplace , or other virtual marketplace) does not have to worry about this problem, since he does not need to travel (which makes the time to find the best solution O(1)), to which the travelling salesman angrily responds, "Shut the hell up."
The title text wonders about the time complexity of the cutting-plane method , which is sometimes used to solve optimization problems.
The last sentence suggests the downside for Randall of drawing comics about computer science; he sometimes encounters problems to which he cannot find the answer, whereas authors of simpler comics such as Garfield do not have this problem. This is also likely a reference to 78: Garfield , which parodies Garfield's simplicity.
The map almost certainly depicts the United States, with the locations highlighted suspected to be (from left to right): Seattle, San Francisco, Los Angeles, Phoenix, Denver, Minneapolis, Dallas, San Antonio, Houston, Chicago (cut off), Detroit, Atlanta, Miami, Washington D.C., Philadelphia, New York, and Boston.
This is so far the only comic featuring the Brown Hat character.
Also see earlier strip 287: NP-Complete .
[There is a linked black web, with a path in red; it appears to be a map of the United States.] Brute-force solution:O(n!) [The web continues in this one. A man with a brown hat and a case is drawing it.] Dynamic programming algorithms: O(n 2 2 n ) [Another man, with a brown hat too, is at a computer, looking back over the chair.] Selling on eBay: O(1) eBay salesman: Still working on your route? Drawing salesman: Shut the hell up.


Important Life Lesson

Explanation:
It's common to have music playing in the background when two individuals decide to engage in sexual behavior. However, some people have a lot of silly or funny songs in the same music library as their more dramatic or romantic song choices. If the library is left to randomly choose songs from the whole library, those more whimsical songs could easily come up, suddenly ending the intimate mood.
Cueball is performing cunnilingus on Megan, while a particularly goofy song, the Power Rangers Theme , plays in the background. The title text alludes to an even sillier song, the Monty Python song Lumberjack , which is about a transvestite lumberjack.
Important life lesson: If there's any possibility of sex, do not leave your music library on "shuffle all." [Megan lies down in a bed, while Cueball is beneath the bed sheets with his head between her legs. On the other side of the room, a computer is turned on and playing music.] Megan: *GASP* MMMMM- Computer: GO GO POWER RANGERS!


Large Hadron Collider

Explanation:
The Large Hadron Collider (LHC) is the world's largest particle accelerator, used in physics research, and particularly for finding the Higgs Boson . The Higgs Boson is one quantum excitation of the Higgs Field, in the same way as the photon is a quantum of the electromagnetic field. Interaction between particles and the Higgs field can explain why other particles have mass. The Higgs Boson was first detected in 2012, and confirmed to exist in March 2013. It was the last particle of the Standard Model of Physics to be experimentally confirmed.
At the time of this comic's writing, the LHC was nearing completion, and the comic imagines experimental physicists starting up the LHC for the first time. It has taken many years to complete, and its intended purpose was to be able to measure the Higgs Boson. In the comic, the experiment fails to observe the Higgs Boson. The researchers can only wait for the theorists to determine what may have happened, if something went wrong, or if they can come up with a testable hypothesis. In 2012, and after many years of experimentation and observation, the Higgs Boson was observed at CERN's LHC. This comic imagines what the researchers may have done with the LHC in between tests.
After the experiment failed, the bored physicists try frying pigeons with the proton stream and instead end up giving a helicopter cancer, both of which are impossible. This is because the stream is contained within the LHC, and non-organic entities can't get cancer [ citation needed ] . However, the proton stream could cause considerable damage to pigeons or humans, as the U-70 synchrotron did to Anatoli Bugorski in 1978.
At that time there was also a big concern by some people that the LHC could produce microscopic black holes . However, cosmic rays regularly strike Earth's atmosphere with particles at higher energies; thus, if the proposed doomsday scenario were possible, it should have already happened. Many jokes were published like this video "LHC End of The World Black Hole" .
The title text makes another joke about the effects of highly energetic particles, claiming that when they pass through a bubble chamber (an older particle detection device), they leave a trail of candy. TeV means tera electronvolt and equals 10 12 eV. 5 TeV is about the energy of the LHC. It is of the order of the energy of a flying mosquito and would never be able to convert a liquid to candy or anything macroscopic.
The Large Hadron Collider, CERN... Megan: Okay, moment of truth. "click" Large Hadron Collider: "VVVVVRRMMMMMM" Cueball: Do you see the Higgs Boson? Megan: Nope. Cueball: Huh. Megan: Well, then. Cueball: Until the theorists get back to us, wanna try hitting pigeons with the proton stream? Megan: Already on it. Cool! I just gave a helicopter cancer.


1,000 Miles North

Explanation:
Spoofing off of tornado chasers are these permafrost chasers, who are just like tornado chasers, but they are chasing very boring [ citation needed ] permafrost. Permafrost is a layer of ground that never thaws, unlike ground closer to the equator, where the ground freezes in winter and thaws in the spring.
The title text references the 1996 movie Twister about a crazy group of tornado chasers trying to drop a probe-releasing device named Dorothy (based on the real-life project TOTO ) into the heart of a tornado.  However, much of the story was about Bill and his ex, both chasers, falling back in love, another chaser who is fighting Bill for research grants and fame, and a tornado that likes to chase people. Randall comments that the movie would have been better if they had lost all of the above except the tornadoes and the scientist, which is basically all you need for a good movie. And then he continues his musings by saying that tornadoes and scientists "are all you need for anything."
This seems to be the first comic mentioning tornadoes, but since then they have become a recurring subject on xkcd, and in the next two tornado comics, 640: Tornado Hunter and 752: Phobia , tornadoes and tornado chasers are actually featured.
[A van (almost exiting the frame to the right) and a pickup truck behind the van are driving on a road where dust blows up behind the tires. There are three mountain peaks in the background. In the rear of the truck is a cylindrical-shaped object. Above the truck there are two frames with yellow background and text. The top frame is at the height of the mountains, the other just above the truck.] 1,000 miles north of tornado alley A new breed of scientists has emerged.
[At the base of a mountain (or glacier front) to the right, Cueball runs towards Ponytail (as shown with a curling line behind his raised leg). He is carrying a laptop in his arms, and he has a headset with antenna and microphone on. Ponytail is holding a probe in both hands, maybe drilling it into the ground. Grass and small rocks are drawn around them. At the top is another frame with yellow background and text.] Half researchers, half adrenaline junkies Ponytail: What's the reading? Cueball: 3.9 meters down, gradient's off the charts!
[The pickup truck is shown in a zoom in from the side. Cueball is driving very fast, while holding a Walkie-talkie up to his head. The cylinder in the rear, from the first frame, now clearly turns out to be some kind of instrument with a small parabolic disc and a smaller antenna, and there are some labels and a text is written across it, although it is difficult to read. At the top is another frame with yellow background and text.] Risking everything for the thrill of the hunt Cueball: The freeze line is shifting! We've never seen anything like it! Cylinder: Riwan
[Ponytail is holding a large video camera down towards a tiny spot of grass on the ground. He is standing in a barren field with one small mountain to the left and three small mountain peaks to the right in background. Behind him is a large box connected to a small radio with a long antenna. Cueball speaks to him over his walkie-talkie, his voice coming from the radio via a zigzag line. At the top is a final frame with yellow background and text.] Permafrost chasers Ponytail: I'm getting some great footage here! Cueball: Dammit, Harding, it's not worth your neck! Get the hell out of there!


Convincing Pickup Line

Explanation:
A graph is a mathematical object consisting of nodes connected by lines called edges . The nodes could represent for example people, and the edges could represent a connection from having slept together. Now, Megan has such a graph. Arguably, a graph that is symmetric is nicer than a regular one, which is why Megan suggests that they should sleep together.
The title text is a small-world joke on the concept of an Erdős number . Paul Erdős was a Hungarian mathematician renowned for his eccentricity and productivity. He holds the world record for the number of published math papers, as well as for the number of collaborative papers. A person's Erdős number is the "collaborative distance" between the person and Erdős. Paul Erdős's Erdős number is 0 by definition. All of his 511 collaborators have the Erdős number of 1; anyone (excluding Erdős) who has collaborated on a mathematical or scientific paper with any of those collaborators has an Erdős number of 2, and so on. Thus, if you have written a paper with someone who's written a paper with someone who's written a paper with Paul Erdős, your Erdős number is 3. If you know a mathematician or are a mathematician, you can calculate their or your Erdős number here .
This may also be a reference to Chapter 4 of Candide , wherein Pangloss tells the protagonist of the genealogy of his syphilis.  He received the disease from Paquette, who acquired it from a Franciscan , as so on until the lineage starts with one of the adventurers of Christopher Columbus .
In 599: Apocalypse , Cueball actually manages to write a paper with zombie Erdős, thus having a Erdős number of 1.
[Cueball and Megan sit at a small table in a cafe. Megan holds up a graph.] Megan: We're a terrible match. But if we sleep together, it'll make the local hookup network a symmetric graph. Cueball: I can't argue with that.


Not Found

Explanation:
There is no image for xkcd comic numbered 404. Randall did, however, not skip a day!
The previous comic 403: Convincing Pickup Line was released Monday March 31st 2008, and he put the next comic, 405: Journal 3 , up as scheduled on Wednesday April 2nd 2008, which leads some to see the 404 as an April Fools' Day joke released in between, as comic 404: Not Found released on Tuesday April 1st 2008.
This was thus the first April Fools' comic released by Randall (not counting the unnumbered Syndication released the previous year). The next (and first real) April Fools' Day comic was not released until 880: Headache on Friday April 1st 2011, although Randall did make other jokes in the years in between.
"404" is the HTTP Response Code for " Not Found ." Randall deliberately skipped comic number 404 in xkcd. Therefore, when people go to xkcd 404 , they get a "404 Not Found" error page. (This does not work in all browsers. In newer versions of Internet Explorer, a message about the link being broken occurs without the 404 code.)
Randall has stated that he considers 404 an official, actual comic, albeit a rather avant-garde one , and that for a time he made it possible to find it using the "random" button on xkcd.com. He once again displays this in the 2018 April Fools' joke, 1975: Right Click , where you can access all of his comics up to Right Click from the right click menu, and the menu includes this one specifically due to the strange "title"!
It may seem like a random coincidence that xkcd 403 came out the day before April 1st 2008. And for sure it must have been by chance that it would come out close to that date when Randall began posting on xkcd. But when Randall noticed this fact, at some point prior to that date, he would, however, have had a chance to influence the release date. In November 2007, less than half a year before this April 1st, he released the 1337 series over five consecutive days. That would have moved the release date of 403 from Friday the 4th of April to the Monday it was actually released - making it possible to skip comic 404 as if it came out on April 1st without skipping a comic on a normal release day. There was at least one other series in 2007 to use all five days of a week ( Choices ), so maybe he had this planned for a long time?
It is perhaps an interesting point that the very next comic, 405: Journal 3 , includes the line "So, you found me after all."
In 1969: Not Available , the error message 404 is referenced in the caption.
This is featured in a few comics to come, including 1975: Right Click (in File > Open > C:\ > Bookmarks/ > Comics > comic num 404).
[Instead of the regular xkcd site layout, just a white page that states on top center:] 404 Not Found
[Page-wide divider line]
[Below that in a smaller font:] nginx
It thus leaves the xkcd page.


Journal 3

Explanation:
In Journal 1, Black Hat explains to Cueball that a hobby of his is to pretend to write in a journal while on the subway, acting embarrassed if anyone sees. He then proceeds to silently scorn the person once they give him any kind of reassurance.
In Journal 2, however, Danish sees through his ruse. She counteracts it by proving that she understands him, and attempts to resign him to the fact that he will never see her again, thus robbing him of the satisfaction of a proper social connection. She leaves, taking his hat in the process.
Initially stunned, Black Hat seems to have quickly recovered and tracked Danish down, even to the ends of the earth. He tells Danish that although she was able to read him brilliantly, she miscalculated one minor detail. We are led to believe that this is some mistake in the covering of her tracks, but then he explains that it was simply how much he values his hat. It may also be the possibility that Black Hat placed a tracking device of some sort on his hat. This way he gets back at her. She thought that he would mourn the loss of her - the only person who understands him - but he deflates her ego when claiming that he likes his hat (implicitly saying that he doesn't care for her). The series continues in 432: Journal 4 .
The title text continues the theme of Black Hat's superhuman ability to troll and to avoid the consequences: If Black Hat stole a military submarine, said military is probably going to be hot on his tail, but he writes it off with: "just tell them it was always here," as if it is no big deal. Black Hat will even be blamed for stealing the submarine in 496: Secretary: Part 3 . However, since this is (presumably) the American Senate reviewing him, it may be that he simply has stolen two submarines.
It is perhaps an interesting point that this comic includes the line "So, you found me after all," given that the previous comic number xkcd 404 was skipped, leading instead to an HTTP 404 Not Found error page.
The whole " Journal " story is:
[Two women ice-skating outside.] Ponytail: Wait up! Danish (wearing Black Hat's Hat): Skate faster!
[Danish sees cracking ice.] Crack Crack
[Danish on chunk of ice broken off.] Crack Rumble
[Submarine dorsal fin emerging.] AWOOGA
[Black Hat (minus hat) coming out of hatch.] CREAK Black Hat: Hi.
Black Hat: That's my hat you're wearing.
Danish (wearing Black Hat's Hat): So, you found me after all. Black Hat (out of frame): You didn't make it easy.
Black Hat: You saw through me, all right. But not quite well enough.
Black Hat: Because if you wanted to stay lost forever, you made one mistake
[Black Hat climbing out of hatch.]
[Black Hat sliding down a sheet of ice.]
[Black Hat snatches hat from Danish's head as he slides by on the ice.]
[Black Hat skidding to a stop and putting hat back on his head.]
Black Hat: You took my hat.
Black Hat: I LIKE my hat.
[Black Hat walking away.]
[Danish left standing.]


Venting

Explanation:
This is yet another xkcd comic referencing Firefly , but it's not so much about Firefly itself as about Summer Glau . Summer Glau is an American actress best known for playing River Tam in Firefly and Serenity , as well as Cameron in the Terminator: The Sarah Connor Chronicles series.
Cueball says that he gives a long and seemingly well-researched reply to a stupid comment on a blog when he feels angry as a way to vent. What we see of his comment begins with Cueball describing the original comment's incoherent and inconsistent spelling and grammar. Then, he proceeds to rip apart the commentator by citing their historical and political ignorance. He signs his comment as 'Summer Glau', after which he reminds the blogger to watch the next season of Terminator: The Sarah Connor Chronicles series .
One likely reason that he uses 'Summer Glau' is that she is worshiped by geeks the world over, even those incapable of writing coherent blog posts or comments. CrackMonkey74 would not risk responding negatively to the post, just in case it was actually written by Summer Glau, as they don't want everyone to hate them for attempting to argue with her. In this way, Cueball is assured of the last word in this argument, which makes for a most satisfying vent.
Another possible explanation is that River Tam has a genius-level intellect and is also mentally disturbed. Given xkcd's trend of comparing Firefly characters to their respective actors (especially in The Race ), Cueball is probably using Summer Glau's name simply because an exhaustively researched blog comment seems like something River Tam -- and thus possibly Summer Glau -- would do.
The title text refers to the famous dialogue delivered by River Tam in Firefly Episode 11: " Trash ".
[Caption above the panel:] When I need to blow off steam, I find a particularly stupid blog comment and reply with an exhaustively researched word-by-word rebuttal, which I sign 'Summer Glau'.
[Cueball is sitting at a desk, typing in front of a monitor. A curved line leads up from his hands to the text above.]
In conclusion, on examining the above post by CrackMonkey74, after carefully working my way through the haze of spelling errors (documented in section 3), abuse of capitalization (section 4), and general crimes against grammar and syntax (sections 7-8), I have demonstrated that, beneath it all, the work betrays the author's staggering ignorance of the history and the workings of our electoral system. While the author's wildly swerving train of thought did at one point flirt with coherence, this brief encounter was more likely a chance event (see statistical analysis in table 5) than a result of even rudimentary lucidity. -Summer Glau P.S. Don't forget to check out the next season of the Sarah Connor Chronicles this fall on Fox!


Cheap GPS

Explanation:
GPS is a system allowing people to find their location and from that, speed on Earth. It was first developed for the U.S. military, but now it sees international usage for everyday navigation. Many motorists today have GPS devices (sometimes just called GPS's) that can give driving directions electronically.
Hot and Cold is a children's activity/game where one person searches for an unknown object, and the rest must respond "Hot" or "Cold." Other words, such as "warm" and "cool" can be used to describe their distance more accurately. The closer the player is to the mystery object, the "hotter" they are.
This GPS would be extremely difficult to use, as it gives no directions, only telling you how close you are to reaching your destination. The series of instructions spoken ("cold," "warm," "hot," then "cold" again) suggests that Cueball either missed a turn, or that he just passed his destination.
Randall describes a past engineering project of his that can only describe turns "as the crow flies." So, for example, if he was driving north with the destination to the northeast, the GPS would tell him to turn right even if no such turn was legally possible. Perhaps not very functional, but it is a pretty cool thing to build.
While cars go fast and are only allowed to, or able to, use a very limited number of all roads and trails in the world, this is less so for pedestrians. As a consequence, for hikers, an app that just shows the direction you should be walking in 'as the crow flies' is actually quite a common and useful tool, since a lot of small roads suitable for pedestrians do not show up on maps. Of course, just printing 'left' or 'right' is much more primitive than showing an arrow in the correct direction (compass-like), and often less helpful since on one cross section there can be multiple trails to the right.
[Cueball driving down the road, with a GPS reading "COLD."] GPS: COLD... WARM... HOT! COLD...


Overqualified

Explanation:
Megan 's sister has a crush on Cueball , but Cueball doesn't feel the same way about her sister. To alleviate the situation without hurting Megan's sister's feelings, Megan wants Cueball to deliberately take her sister out on a bad date to convince her that Cueball is not worth dating, so that her sister can move on without rejection. Cueball is excited to finally excel at dating badly. He claims to have been born for the task of giving a bad date. He promises to emulate one of his classic high school dates, indicating that they went terribly as well. The joke is based on the reversal of expectations and Cueball's subsequent excitement at the chance to provide a terrible date. Megan's response of "Oh God, don't overdo it" may also imply that she was one of Cueball's high school dates and doesn't want her sister to be subjected to what she remembers of Cueball's approach to relationships.
The title text implies that Randall is reflecting on previous bad dates. When they occurred, he had either no excuse or a poor excuse for why he was so awkward, but now "deliberately being mediocre" is going to be used as his explanation. It is similar to thinking of a good comeback to an insult after the fact; this is his retort to ships that sailed long ago.
[Megan on the phone.] Megan: I know you're not that into my sister, but she's really crushing on you. Cueball: Yeah, it's awkward.
Megan: She's in a rough spot. It's a lot to ask, but could you take her out and... Dissuade her, without rejecting her?
Cueball: Wait a second. Are you asking me to show her a mediocre time? Megan: I know it's a weird—
[Cueball raising index finger.] Cueball: No, no! This is the mission I was born for. Megan: I figured you could handle it. Cueball: One of my classic high-school dates coming up! Megan: Oh God. Don't overdo it.


Electric Skateboard (Double Comic)

Explanation:
This comic is an affectionate parody of Calvin and Hobbes , a newspaper comic drawn by Bill Watterson that ran for ten years from November 1985 to December 1995. Calvin and Hobbes follows the daily life of a rambunctious, precocious six-year-old named Calvin and his sarcastic stuffed tiger Hobbes. The artwork in the second strip is distinctly Wattersonian as well. This comic could be referencing the typical Sunday strip format of having a top line of "throwaway panels" that had a one-off gag before the rest of the strip, which was more detailed. This was an effect of Sunday strip formatting in newspapers, where individual newspaper often lopped off the top one-third of the comic to save space. Thus, strip creators had to use the top panels on throwaway gags or else the readers of a space-saving newspaper would be missing key parts of the strip.
Calvin and Hobbes is also referenced in 529: Sledding Discussion .
Randall has a special fascination with motorized skateboards . A longboard is a skateboard that is longer, used for downhill races, and skating through less urban areas (college campuses, for example).
Mario Kart is a game series for Nintendo game consoles that allows four players to race each other while having good spirited fun like at 290: Fucking Blue Shells while throwing items at each other. The objects in the fourth panel are Koopa shells, items in the game. They can be thrown like projectiles to crash into foes: green in a straight line, red homing onto the racer directly in front. They also come in single and triple varieties. In Mario Kart: Double Dash!! , two racers occupy the same vehicle, with each possessing their own item slot (in contrast with most games in the series, in which a single vehicle can only have a single item ready, and must use it to obtain another). This is reflected in the drawing of Cueball and Megan together on the electric longboard, with Megan using a Red Shell and Cueball holding the triple Green Shells.
Calvin and Hobbes frequently involves heavy philosophical discussions. In one recurring theme, they ride down a dangerous hill in a red wagon or toboggan while discussing the nature of morality, usually ending in a crash (examples [1] [2] [3] ). This comic inverts that by having Cueball and Megan go uphill while discussing philosophy. Naturally, they collide with Calvin and Hobbes' wagon - which prompts the title text.
Cueball uses the C and Python programming languages as analogies for their ride. In general, Python is easier than C and abstracts a lot of C's hairier features ("boring parts," as Randall calls them). Moving from C to Python is quite a freeing experience ; programmers no longer have to worry about pointers and memory allocation, and it just lets the code flow through the programmer until they are one with the Force. Erm, computer. Although, it seems that - before the crash - the idea that programming in C (and skating without electricity) building character is about to be explored philosophically (building character is also a recurring theme in Calvin and Hobbes, as documented delightfully in the Calvin and Hobbes wiki ).
Electric skateboards have been the subject of several other comics like 139: I Have Owned Two Electric Skateboards , a panel in 442: xkcd Loves the Discovery Channel , and the entire The Race five part comic series.
[Cueball showing off electric skateboard to Megan reading something.] Cueball: Check it out! An electric longboard! Megan: Sweet!
[Cueball riding longboard with Megan sitting onboard — people in background.] Longboard: RRRR
[Megan turned around on longboard.] Megan: I feel like we're missing something... Cueball: Yeah...
[Cueball holding 3 green Koopa Troopa shells; Megan throwing 1 red Koopa Troopa shell - like Mario Kart.] Music Playing Longboard: RRRR

[Cueball and Megan still on longboard, going up an incline.] Cueball: Skating uphill like this is amazing. Years of gliding downhill and pushing uphill, and now suddenly it's gliding both ways. Longboard: RRRRRRR
[Cueball and Megan after passing an S-curve and boulder.] Cueball: It's like going from C to Python. You don't realize how much time you were spending on the boring parts until you don't have to do them anymore. Megan: But coding C or assembly makes you a better programmer. Maybe the boring parts build character.
[Cueball and Megan on longboard.] Cueball: Yeah... but it depends how you want to spend your life. See, my philosophy is- [Longboard gets into an accident.] WHAM
[Calvin and Hobbes lying down in the grass near Cueball and Megan lying down in the grass - Calvin and Hobbes's wagon is on the path, as is the longboard - all characters seeing stars.]


Math Paper

Explanation:
The math paper Cueball is in the process of describing in this comic turns out to be nothing but an elaborate setup for a joke about imaginary friends by taking the concept of " friendly numbers " into the complex (imaginary) plane, which comprises complex numbers that have both a real and an imaginary part (see details below ).
Cueball is challenged on this setup by his superiors, specifically the Cueball-like guy sitting at the end of the table, who look straight through his first line-up for the joke, and ask him directly if this is just a build-up for this joke. Cueball tries at first to look like he has no idea what he's talking about, then lowers his head, in shame, and finally tries to state that it might not be such a setup. But it is too late now.
Such a pun is both so obvious and so terrible that Cueball's superiors deem that he should no longer have a license to math , and they thus revoke Cueball's "math license." Of course you do not need a math license [ citation needed ] , but that is part of the comic's concept along the lines mentioned here below and further elaborated in the title text.
It is a recurring theme in earlier xkcd comics that Cueball (or Randall ) ends up being banned from holding presentations at conferences after a presentation turns out to be just an elaborate pun.
The title text takes the joke a step further, with the added hilarity of making the audience question exactly how Cueball/Randall was able to work a striptease into a presentation about genetic engineering and astrophysical rocket study (or possibly genetics and rockets into a striptease), and then even manage to lose all three licenses in one go. This is what TV Tropes calls a " noodle incident ."
The whole comic is basically Randall making the joke that Cueball never got around to, but packing it up so we think it is about something else. Randall has often made such feeble jokes, but by putting them into a context where someone listening may comment on how bad that joke is or have to explain the joke, it somehow becomes alright, and he can get away with these jokes anyway. (See for instance 18: Snapple ).
An imaginary number is a number that can be written as a real number multiplied by the imaginary unit i , which is defined by its property i 2 = -1 (an impossibility for regular, " real numbers ," for which all squares are positive). The name "imaginary number" was coined in the 17th century as a derogatory term, since such numbers were regarded by some as fictitious or useless, but over time, many applications in science and engineering have been found.
An imaginary number bi can be added to a real number a to form a complex number of the form a + bi (the formula shown at the bottom of Cueball's slide ), where a and b are called, respectively, the real part and the imaginary part of the complex number. If a and b are both integers, the complex number is called a Gaussian integer (as Cueball mentions). The complex plane is an X-Y plot with a on the X axis and b on the Y axis. (Such a plane is shown at the bottom of Cueball's slide).
Joel Bradbury (once) had the below cited and wonderful explanation of friendly numbers on his site:
What are Friendly Numbers? We need first to define a divisor function over the integers, written σ(n) if you're so inclined. To get it first we get all the integers that divide into n. So for 3, it's 1 and 3. For 4, it's 1, 2, and 4, and for 5 it's only 1 and 5.
Now sum them to get σ(n). So σ(3) = 1 + 3 = 4, or σ(4) = 1 + 2 + 4 = 7, and so on.
For each of these n, there is something called a characteristic ratio. Now that's just the divisors function over the integer itself: σ(n)/n. (This is the formula shown at the top of Cueball's slide). So the characteristic ratio where n = 6 is σ(6)/6 = 12/6 = 2.
Once you have the characteristic ratio for any integer n, any other integers that share the same characteristic are called friendly with each other. (This is what is written in the frame in Cueball's slide, spelling friendly numbers as friendly #s ). So to put it simply, a friendly number is any integer that shares its characteristic ratio with at least one other integer. The converse of that is called a solitary number, where it doesn't share its characteristic with anyone else.
1, 2, 3, 4, and 5 are solitary. 6 is friendly with 28; σ(6)/6 = (1+2+3+6)/6 = 12/6 = 2 = 56/28 = (1+2+4+7+14+28)/28 = σ(28)/28.
[Cueball, holding a pointing stick, is using it to point at an equation on a panel. He is looking to the right. There are several parts of the panel that can be read. At the top, there is a formula. Below is a frame with text. Below again to the left is an X-Y plot with small dots all over all four quadrants, probably indicating the complex numbers with b on the Y and a on the X axis. Finally, right of this is yet another formula.] Cueball: In my paper, I use an extension of the divisor function over the Gaussian integers to generalize the so-called "friendly numbers" into the complex plane. Panel: σ(n)/n = d(n) Friendly #s share d(n) For a + bi...
[The audience to the right of Cueball consist of two Cueball-like guys (one in front and one in the back), and between them are Hairbun, with glasses, and Megan. They sit around a table; only Hairbun is on the near side. The Cueball-like guy sitting to the right is at the end of the table, the other two are on the far side. The Cueball at the end of the table is talking, the other three have turned to look at him:] Guy at the end of the table: Hold on. Is this paper simply a giant build-up to an "imaginary friends" pun?
[Back to Cueball, who stands speechless.]
[One more beat panel with Cueball, who now looks down.]
[Zoom out to Cueball and the front end of the table with the Cueball-like guy who has not spoken yet and Hairbun who now looks at Cueball. Cueball looks up again and speaks. The guy at the end of the table speaks off panel.] Cueball: It might not be. Guy at the end of the table (off panel): I'm sorry, we're revoking your math license.


Techno

Explanation:
Cueball points out that due to the repetitive nature of techno music , the iTunes 15 second sample can be used to recreate the entire song. This is for the many repetitions in techno music, usually repeating it 4 (or other powers of two) times.
The title text refers to the clicking and grinding noises of a dying hard drive, a sound similar to some techno songs. The title text suggests that this actually exists: an example is here .
Techno music is also mentioned in 586: Mission to Culture and 740: The Tell-Tale Beat . Sampling and looping sounds that aren't necessarily musical is mentioned in 2427: Perseverance Microphones .
[Cueball looking over Megan's shoulder while she is clicking her mouse with her other hand on her chin.] Cueball: Wait, you're buying techno on iTunes? Megan: Yeah. So? Cueball: Couldn't you just loop the 15-second free sample 20 times and get basically the same thing?


Startled

Explanation:
Black Hat , the cool-headed troll, has the tables turned on him. Almost always seen antagonizing other characters, Black Hat is shown in this comic in a rare moment of losing face. Megan notices Black Hat facing away from Cueball and her, and decides to play a simple, childish prank on him: sneaking up from behind and shouting "Boo!".
She succeeds in startling Black Hat. Most likely out of humiliation, he hides himself completely in his hat. For a moment, it looks like Black Hat has disappeared altogether. But then his hat inches away, showing that he's still underneath. It is possible that he was set on edge by Danish, as the period from journals 3-4 was clearly an emotional time for him.
Both gags in this comic work by playing on our expectations. The first is an unexpected moment of realism: we are so used to seeing Black Hat cool and untroubled that we are surprised at the reminder that everyone's appearance is, to some extent, a facade. Black Hat is still human. (The comic 455: Hats is related to this one, as it is also about black hats and how the usually all powerful Black Hat becomes the smaller one, in this case in tallness of hat towers.)
The second gag, on the other hand, is the opposite: we are so used to understanding the stick figures (and specifically the established character that is Black Hat) as representing regular humans, albeit ones with larger-than-life personalities, that we're caught by surprise to see Black Hat so thoroughly defy realism in a fashion not unlike what one could find in a Tex Avery-type cartoon. Among the further interpretations of the gag, one could see:
The title text is only "...", implying that Randall himself shares the reaction of Cueball and Megan, who are left speechless and immobile in the last panels, as Black Hat completes his physics-defying stunt. The same title text is used in 82: Frame and 455: Hats . One could say of these comics that they're somewhat surreal, and any further commentary might have detrimentally brought them down to Earth.
[Wide panel. Cueball and Megan are standing to one side. Black Hat is standing some distance away. Megan is looking at Cueball while pointing both at Cueball and at Black Hat.]
[Normal sized panel. Zoom in as Megan sneaks up close to Black Hat, who now looks a little upwards.]
[An inserted panel only half the height of the normal panels, but with its top lifted slightly above their levels and with its frame crossing both the previous and the next normal. It shows a close-up of Megan with hands raised while shouting.] Megan: Boo!
[Only Black Hat is shown in this thin panel. He looks shocked, which is indicated by him taking his hands to his face, lines behind his head, and that his hat jumps up above his head, showing that he has a bit of hair under it.]
[The next three panels are even thinner than the previous, but they stay the same size. First, the hat falls down over Black Hat's head down to his shoulders, without the hat changes size. The movement is indicated with two lines above the hat. Black Hat crosses his arms across his chest and bends in the knees.]
[Then the hat keeps falling over his body, swallowing it so only his legs below his knees are visible.]
[Finally the hat hits the ground with a large sound, also indicated with seven "U" shaped lines around the hat. There is no sign of Black Hat.] Fwump
[The last two panels are in another row below the previous panel, but there are no panels under the two first panels in the first row. This could indicate that time has passed, or is just a way to create a dramatic effect, as with all the other changes in panel size and position above. This panel's width is somewhere between the first two panels. Cueball and Megan look at the hat, Cueball with a hand in front of his mouth.]
[The last panel is as wide as the first, but extends farther to the right than the last panel in he first row, again breaking the symmetry. Megan and Cueball still look on (both with hands down) as the hat begins to crawl away. The movement makes sounds and is indicated with four lines behind the hat now farther away from the two.] Scooch Scooch Scooch


New Pet

Explanation:
Megan and Cueball create a new pet by putting an Eee PC into a hamster ball , allowing it to roll around.
The Asus Eee PC was one of the first subnotebook computers available on the American market, noted for its small size and coming pre-installed with Linux. With a diagonal size of 11 inches, it would take a big hamster ball to carry it like this.
Omniwheels are wheels with rollers mounted on the edge to allow the wheel to slide sideways. The wheels in the drawing look more like Mecanum wheels , which have rollers mounted at an angle to the edge. Both omniwheels and Mecanum wheels are used in omni-directional drive systems, like you would use to drive a hamster ball from the inside. A webcam is connected magnetically to the top of the hamster ball, which connects to an rf link to transmit wirelessly to the computer.
TCO is total cost of ownership , which is exactly what it sounds like: the purchase price of something, plus all costs of keeping, operating, and/or maintaining that something. It's used in accounting to determine something's true cost-to-value evaluation. In the case of a cat, TCO would primarily consist of food, litter, veterinary care, etc. Refer to trivia for more details . For the device in the comic, there would be a small ongoing cost (occasional recharges for the batteries) after the initial investment.
A Roomba is a self-directed robotic vacuum cleaner made by iRobot, which has no feelings and cannot make friends. [ citation needed ]
Python is a programming language popular among geeks running Linux. Among other features, it has a large number of easily installed 3rd-party libraries that make it easy to add features to programs. In this case, Cueball is importing the "soul" library to give the new pet a soul – something that a programming language cannot actually do. [ citation needed ]
The title text refers to the One Laptop per Child project spearheaded by Nicholas Negroponte around 2005, with the goal of building an inexpensive, durable sublaptop that could be distributed to children in developing countries to give them an educational edge.
[Megan is placing EEE PC inside hamster ball. Cueball scratches his head.] Cueball: What are you doing? Megan: Mounting your EEE PC in a hamster ball.
Megan: Well, the TCO of a cat is like $1,000/year, so we're saving money.
[Cueball is typing.] Megan: Microcontrollers are all wired up! How's the brain coming? Cueball: I've taught it obstacle avoidance and blogging.
Cueball: Aww, look, it's making friends with the Roomba. EEE PC: RRRRR Roomba: Beep!
[A blueprint in the background shows a webcam, RF links, bearings, omni wheels, magnets, EEE PC, omni wheels, and a battery all hooked up to Megan and Cueball's "pet."]
[Hamster ball bounces down a flight of stairs.] Hamster ball: Bonk bonk Off-panel: Man, I hope it's okay that we're laughing at this.
[Megan picks up a ball.] Megan: I think my mothering instinct took a wrong turn somewhere. Cueball: You mean an awesome turn.
[Cueball is typing.] Megan: Too bad we can't give it a soul. Cueball: Sure we can. Cueball types: import soul Megan: Oh, right. Python.


Mistranslations

Explanation:
The Kama Sutra is a well-known work on human sexual behavior originally written in the language Sanskrit, in India sometime between 400 BCE and 200 CE. It's not exclusively a "sex manual," as it also contains a guide to virtuous and gracious living, but in the Western world, it's primarily thought of as a manual of exotic sex positions.
Given that the Kama Sutra was written almost 2,000 years ago, it's doubtful that it has any references whatsoever to a skateboard ramp, but Cueball and Megan enjoy their badly-translated version of the Kama Sutra so much that they refuse to change it.
The title text refers to Crisco , a brand of shortening that is used in baking, as well as a sexual lubricant. It has been mentioned before in 330: Indecision and later in 557: Students .
[A bed sits on the ground in the middle of the frame. At the left of the frame, Cueball stands atop a skateboard jump ramp twice his height, one foot on the back of a skateboard poised over the coping. At the bottom of the ramp is a small kicker ramp, which will launch him over the bed. Megan, to the right of the frame, stands on the roof of a house grasping a rope, which is affixed directly over the bed. They are both poised to begin their motion.] Our copy of the Kama Sutra has a couple mistranslations. Which we refuse to fix.


Restraining Order

Explanation:
A restraining order is a legal injunction requiring a party to do, or refrain from doing, certain acts under penalty of fines or imprisonment, designed to safeguard the complainant's life. In general, the forbidden act is virtually always contacting the complainant in any way and enforcing that they remain a minimum distance from the complainant.
However, Ponytail has taken the concept into the realm of the absurd, issuing a restraining order against Cueball that requires him to stay between 500 yards (~457 m) and 600 yards (~549 m) of her at all times. Needless to say, this will cause a major disruption to his life; the title text gives an example in which he is forced to imitate her jogging routine just to avoid breaking the order. What isn't explained is how Cueball can possibly keep himself within the ring if she happens to travel by airplane or ferry. This, and because there are virtually no useful scenarios for it, [ citation needed ] is why maximum distances are never enforced in real life; such an order would grant the complainant carte blanche to unjustly manipulate the defendant.
A yard is a unit of length used in the UK and the United States. 1 yard = 0.9144 meters.
[Cueball and Ponytail stand facing one another. Both hold sheets of paper. Cueball holds a restraining order, while Ponytail holds a map with two concentric circles drawn on it.] Not content with normal restraining orders, my ex got creative. Cueball: Wait... I can't get closer than 500 yards of you... or more than 600 yards away? Ponytail: You'll have to move somewhere within this ring.


Zealous Autoconfig

Explanation:
Cueball is seen in an attempt to connect his laptop to a Wi-Fi network using, as the comic title suggests, a particularly zealous "Wifi Autoconfig" utility — "zealous" being a synonym for "eager" or "enthusiastic." The utility manages to find a secure access point named "Lenhart Family," presumably Miss Lenhart 's home Wi-Fi access point, and attempts to connect to it.
Instead of requesting a password, the program automatically begins a dictionary attack , entering in various commonly-used passwords in the hopes that Miss Lenhart has little regard for proper security measures (a flaw shared by many computer users). When this fails, the program attempts to exploit a WEP vulnerability, which surprises Cueball. This also fails, possibly because Miss Lenhart used WPA instead of WEP.
In the third panel, the autoconfig then connects to Cueball's Bluetooth phone and uses it to call a local school in order to locate the Lenhart children, who are attending there, and it reports that it has found them. It acts on this information in the fourth panel, notifying "field agents" to kidnap the Lenhart children for nonmonetary ransom, and then reports that the children are acquired (very fast it seems). With the children as hostages, the program begins negotiations with the parents, offering their safe return in exchange for the Wi-Fi password.
This puns on the computing sense of "negotiation": network protocols (such as HTTP) often specify routines whereby a server and a client computer can agree on the best format in which data can be transferred. This is called content negotiation or format negotiation (see for example section 3.4 of the specification for "semantics and content" in HTTP ).
Cueball, frightened by these actions, repeatedly presses Ctrl+C in an attempt to cancel the process, with little success. Ctrl+C is used to abort programs started from a terminal (Unix/Linux) or a command line prompt (cmd.exe under Windows). (The alternative use of Ctrl+C in many Windows programs, as a shortcut for copying a text selection, is probably not what Cueball has in mind at this point.) Part of the humor is that he only attempts to cancel quite late in the process, well after (for instance) the school was first called, probably because of a morbid curiosity to see what happens.
The title text mentions Ubuntu , a Linux distribution that attempts to be as user-friendly as possible. Randall mentions that he has heard that this "user-friendly" Zealous Autoconfig option has already been installed in the latest Ubuntu release....
Problems that arise when you leave decisions to a computer program are also explored in depth in comic 1619: Watson Medical Algorithm .
[Cueball is sitting on a chair with his laptop in his lap. The text written on the laptop is shown above him, and there is a zigzag line from the laptop to the bottom of the last sentence.] Laptop: Starting WiFi autoconfig... searching for WiFi... Found no open networks. Laptop: Found secure net SSID "Lenhart Family"
[Same setup, but Cueball has changed position. This time there are two zigzag lines between the two sentences from the laptop.] Laptop: Trying common passwords... Failed. Checking for WEP Vulnerabilities... Cueball: Um. Laptop: None found.
[Cueball is still sitting with laptop in his lap, but his hand is on his chin. A phone on table across room starts vibrating. Again only one zigzag line to the bottom sentence.] Laptop: Connecting to Bluetooth phone... Calling local school... Laptop: Found Lenhart children.
[Zoom back to Cueball, who is furiously typing on his laptop, legs stretched out.] Laptop: Notifying field agents. Children acquired. Calling Lenhart parents. Negotiating for WiFi password... Cueball [typing] on laptop: Ctrl-C Ctrl-C


The Man Who Fell Sideways

Explanation:
This comic is humorously built-up like a short drama story, about a man (Cueball) with an unusual physics condition.
It might have been inspired by the Uncle Scrooge adventure comic " A Matter of Some Gravity " ( Inducks ) by Don Rosa , in which Magica de Spell makes gravity pull sideways at Scrooge McDuck and Donald Duck .
The same topic is covered by 1996 graphic novel L'enfant penchée ( The Leaning Child ), but, as it was only published in English in 2014, it’s very unlikely to be a source of inspiration for this comic.
"Soon to be a major motion picture" in the title text might refer to The Curious Case of Benjamin Button , a film released later in 2008 (and based on a short story), in which the protagonist Benjamin suffers of the impossible condition of aging backwards.
"Over land... and sea" might be from the song "Nature Boy" by eden ahbez . Nat King Cole sung (the most famous version) about "A very strange, enchanted boy. They say he wandered very far, very far over land and sea."
The title text mentions Jeph Jacques , who runs the webcomic Questionable Content . Jeph has also described the creation of this comic in his blog while working at ezplay company .
When Cueball hits Megan, he knocks her down and "knocks her up", in what is probably intended to be a visual form of antanaclasis . Megan tells Hairy about a person knocking her over and tumbling into the distance. She hints that she is falling for him, which is a joke regarding Cueball's condition.
The baby shares his tendency to be pulled sideways by gravity, but this apparently does not start until she is born, because Megan and the doctor do not seem to have been expecting it.  If gravity had affected the unborn fetus in the same way, Megan would have been able to feel it, would have noticed that her uterus was hanging differently, and would have had difficulty balancing due to the sideways forces.
The last panel is a reference to the opening scene of The Lion King , called 'The Circle Of Life'.
The first part of the comic has some resemblance to this much later comic: 1376: Jump .
[Cueball standing, with a dotted line perpendicular to him and a 30 degree angle going downwards.] From a young age, gravity pulled him wrong. [Cueball bouncing around his house.] Sometimes east, sometimes west. When he was restrained, it grew erratic. WHAM WHAM [Cueball bouncing/rolling on the ground.] So he fell. Cueball: AAAA THUMPA THUMPA [Cueball bouncing/rolling on the ground in a desert.] Constantly Cueball: AAAAAAAAA [Cueball bouncing/rolling off a rock on the ground in a desert.] Over land... Cueball: AAAAA- THUD -A [Cueball bouncing/rolling on the ground in the desert.] Cueball: AAAAAAAAA [Cueball bouncing/rolling on the ground in the desert.] Cueball: A- THUD -AAAAAA [Cueball bouncing/rolling on the ground in the desert.] Cueball: AA- THUD -AAAAA [Cueball skating the surface of the sea.] And sea. Cueball: AAAAAAAAAAAA [Cueball skating the surface of the sea.] Cueball: AAAAAAAA [Cueball skating the surface of the sea.] Cueball: AAAAAA [Cueball skating the surface of the sea.] Cueball: AAAAAAAA [Tree in the savanna, with Cueball off the panel.] He found, where he could, food- Cueball: AAAAAAAAAAAA [Tree in the savanna, with Cueball still off the panel, but zoomed out so that part of Cueball's bounce/roll path is visible.] Cueball: AAAAAAAAA [Cueball upside-down, still bouncing/rolling in the savannah, with a gazelle galloping away from him.] GALLOP GALLOP Cueball: AAAAAAAAA [Savanna with a tree in it.] Cueball: AAAAAAAAAAA [Megan standing, with Cueball off screen.] And love. Cueball: AAAA- THUD -AAAA [Megan standing, with Cueball off screen.] Cueball: THUD ACK CRASH [Cueball crashing into Megan] Cueball: Hiwhat'syourname- WHAM [Megan on the ground, with Cueball off screen.] Cueball: AAAAAAA- THUD -AAA [Megan speaking to Hairy.] Megan: I met this guy. He knocked me over and tumbled into the distance. [Megan speaking to the same man from the previous panel, with Hairy's hand to his mouth.] Megan: We only shared a few seconds, but in his panicked scream I heard something beautiful. [Megan speaking to the same man from the previous panel.] Megan: I think... I think I'm... [Megan speaking to the same man from the previous panel.] Hairy: Falling for him? Megan: I wasn't going to say it. [Megan at hospital with doctor, giving birth.] She never saw him again. But nine months later... Doctor: Okay, push! [Megan at hospital with doctor and new baby, who is bouncing/rolling away.] Doctor: It's a gir- Megan: !! Doctor: Whoops! Baby: Ga! Ga! [Baby bouncing/rolling out of hospital.] Baby: WHEEEEEEEEEEEEE [Baby bouncing/rolling in front of a sunset.] Baby: EEEEEEEEEEEEEEEEEEE The End
There is a fan made animated version of this comic .


Stove Ownership

Explanation:
This comic is a subtle statement on the epiphany many have when they reach adulthood and are on their own for the first time: No one will tell you what to do! Nobody will, however, stop you from making those poor decisions you were refrained from prior to that independence. Eating bacon whenever one wants is among them.
This line graph depicts Randall's health as a function of time after some undefined point. The joke is that his health goes into an immediate deterioration the moment he realized that he could just cook bacon on his stove whenever he wants. When he says "he could cook bacon," he means he has both the will AND means, since the stove is now his own. Before the bacon revelation, his health was actually improving - this may be explained because he was now cooking his own, healthy food rather than getting pizza delivered or having other pre-made foods/junk food.
Frosting (or icing) is something you use to decorate cakes. Many children enjoy frosting so much that they eat it off the cake and leave the rest behind. Frosting in a can, as mentioned in a title text, is convenient because it is instant and not necessary to make from scratch. When Randall came to college, he still had a very sweet tooth, so when he discovered frosting in a can, his health curve at the time also went into decline. However, that turned out to be a phase - he got over it - and he hopes it will be the same with cooking bacon.
There is now also similarly instant, pre-made bacon that can be eaten right out of the box, eliminating the need to put in any effort to prepare it. The sudden drop in health, obviously, is due to the fact that most bacon is pork belly fat, and while high in protein, its irresistible flavor cannot compare to its high fat and cholesterol content. In addition, porkless bacon made from turkey meat is also available in some places.
In the title text of 1674: Adult , it turned out that Cueball was not yet ready to go shopping by himself, even though he was an "adult" and ended up dying of over-consumption of AirHeads , very similar to the frosting in this comic's title text.
Eating frosting out of the can was also referenced in the title text of 1793: Soda Sugar Comparisons .
[A hand-drawn graph is shown.] [On the y-axis:] My overall health [On the x-axis:] Time [The graph is generally steady rising through 3/4 of the x-axis, where it begins a steady decline. A stapled line marks the start of this decline. Below where the line crosses the x-axis, this decline is labeled:] The day I realized I could cook bacon whenever I wanted .


Forks and Spoons

Explanation:
The comic shows scientists testing a new technology to blend species.
They show that their new technology allows them to cross a spork (an even mix between a spoon and a fork) with a spoon to make a new implement that is three-quarters spoon and one-quarter fork. By blending these new fork-spork hybrids and their results together, the scientists could create any mix between a spoon and a fork. (Obviously, regular genetics cannot apply to non-living items such as metal cutlery).
In the second panel, the amounts of spoon and fork are shown with fractions: the number on the left representing the amount of fork, and the right the amount of spoon. The numbers for the cross product below are arrived at by summing each side and dividing by two: (0+1/2)/2 = 1/4 and (1+1/2)/2 = 3/4.
The breeding scheme between the second and the third panel shows at the top how to create a spork from a spoon and a fork, then how this spork could both be bred with either a spoon (as in panel two) or a fork (as shown in the lower right part).
The binary "fork-spoon spectrum" in between the third and fourth panels shows the complete spectrum of sporks from fork to spoon with some of the intermediate steps labeled, the numbers representing how much fork each contains. Since it is a binary spectrum, only fractions with a denominator that is a power of 2 will be possible, i.e. 2^n with n any integer. So in the middle is a spork with 1/2 fork, in between the spork and the spoon there is only 1/4 fork, and in between that and the spoon only 1/8 fork, and so on. Also 3/4 fork is marked, whereas 3/8, 5/8, and 7/8 fork is only indicated on the ruler by small marks. For instance, they could breed a 3/8 fork-spork by mixing a 1/4 fork-spork with a spork.
The comic begins like standard sci-fi fare, where amoral scientists request funding from mysterious benefactors. The dialogue of "You're toying with powerful forces here" and "We know what we're doing" is a classic trope , foreshadowing that things will soon go horribly wrong . It inevitably leads to the humorous incongruity of a sentient spoon-fork-hybrid on a murderous rampage, which is impossible in real life. [ citation needed ]
Rachael Ray and Emeril , mentioned in the title text, are celebrity chefs, and Steven Spielberg is a famous movie director. The joke seems to be that if the laboratory hadn't hired the two renowned chefs, Spielberg wouldn't have heard about the project and would not have made a movie about it - in which the two scientists are killed off horribly (it is probably the scientist from the first panel, Megan , and her friend, Cueball , or the actors hired to portray them in the film). The plot in the comic is very similar to the story in Spielberg's Jurassic Park .
Megan: A spoon crossed with a fork is a spork. Off-panel Megan's voice: Our lab has successfully crossed a spork with a spoon. [Diagram showing the fractions of fork and spoon in each item.] [Chart showing possible combinations of spoons a forks.] Megan, facing audience: With your funding, we could create hybrids in proportions corresponding to any binary fraction . [Fork-Spoon Spectrum.] Audience member: You're toying with powerful forces here. Megan: We know what we're doing. Two weeks later: [Picture of a destroyed lab, with a scientific poster and lab equipment. Two dead bodies, blood everywhere, and a spoon-fork hybrid hopping away can be seen.] Hop hop hop.


Jealousy

Explanation:
In the first four stanzas of this soliloquy, Cueball reminisces fondly about his meeting of Megan at a party where they quickly had a romantic rapport and spent the night together. The next two stanzas are a lamentation that Megan is now married and can never have that same experience again.
The final stanza reveals that this is not merely Cueball waxing poetic about a previous love, but that he is actually making a toast as the best man at Megan's wedding reception - certainly an occasion when it is wildly inappropriate to discuss the previous romantic involvements of the bride. In modern times, it is not unexpected that the bride at a wedding will have had previous relationships with someone other than the groom, but a wedding is no time to mention them.
The title text implies that the groom had no prior knowledge of Cueball's and Megan's dalliance, and therefore the toast is even more inappropriate - going beyond discussing the previous romantic history of the bride, to actually revealing previously unknown such history to the groom.
Presumably, Cueball's having been selected to be best man indicates that he is a good friend of the groom (as the groom normally selects the best man). The title hints that Cueball is envious of the groom, since his previous encounter with Megan clearly did not result in a lasting relationship, while the groom's clearly did. This suggests that he may be intentionally (perhaps drunkenly) making an inappropriate toast to embarrass the couple as a result of his bitterness.
This was only the third time the name Megan was used in xkcd, the first time being in 159: Boombox .
[Dark scene shown, with Cueball and Megan sitting in the moonlight let in by the only window.] Megan and I first met at a party at her sister's. We hit it off, opened up, shared secrets, and talked about everything. Around us, the party waned, but we hid from sleep together, talking through the deepest hours of the night. The dawn found us curled up on a couch, asleep but still together. That experience, connecting with a stranger and falling recklessly in love is one of life's greatest joys. And now that you're married, you'll never experience it again. It's the price you pay for everlasting love. It's a small one, but I hope it stings a little. Anyway, I wish you and Megan the best. ...Hey, man, you asked me to do a toast.


Making Hash Browns

Explanation:
Cueball is attempting to make hash browns . A hash brown is a way of serving a potato where the potato has been diced or shredded in some way, then pan-fried. Cueball's method for making hash browns, though, is rather unique. He is throwing potatoes into the air and striking them with a flaming tennis racket at his friend, who is holding a tray with a dangerously tilting half-filled glass balanced on top. He (the friend) is also holding a fork in the other hand.
The idea is that the tennis racket would simultaneously dice the potato, fry it, and then launch the completed product towards his friend's plate. In reality, this probably wouldn't do much. To properly pan-fry food, it must be cooked in a pan with some oil to lubricate the food, with enough time for the heat to transfer through the oil and spread properly through the food. Hitting a potato with a flaming tennis racket would not cook it, as it would strike it too quickly, and it probably wouldn't dice it either unless the wire of the racket is incredibly sharp. Cueball would probably just end up batting a not even hot, uncooked, unprepared potato at his friend, while simultaneously burning his own hand. In the case that the wires did actually cut through the potato, then the potato would not be moved forward, but actually end up behind the racket.
The title text comments on how many ways this experiment could go badly (14), and jokes that there are even more potential problems (17) if the fork Cueball's friend is holding is a cross-breed. (See 419: Forks and Spoons , which was published only four days earlier. By reading this comic, it should be clear what could go wrong if they were included in the equation - 3 more ways would be a low estimate....)
It's unclear what Randall may or may not have had on his mind with regards to specific ways the situation in the comic could go wrong. But here are several potential ways the activity could go wrong without including Sporks :
[Cueball stands holding a flaming tennis racket. He is throwing a potato in the air as if to serve like a tennis ball. Behind him is a red gas can and a sack of potatoes. Across from him is another person holding a fork in one hand and balancing a serving tray with a glass holding an orange liquid in it.]


A Better Idea

Explanation:
In the United States, prom (short for promenade) is a semi-formal (black tie) dance or gathering of high school students. They normally are awkward experiences for nerdy people.
A LAN party is a temporary gathering of people with computers or game consoles, between which they establish a local area network (LAN), primarily for the purpose of playing multiplayer video games. They are normally very informal.
Cueball and Megan are likely going to prom together, but they stop when they see that there's a LAN party in formal attire, meaning they wouldn't be out of place. The comic title is likely what one or both of them would say in this situation, since the LAN party is probably much more appealing than a formal ball to them.
The title text indicates that Randall would have loved for such a thing to be possible, so much that he very nearly would redo high school just to participate.
[Cueball wearing a bow tie stands holding hands with Megan wearing a dress. On the left, there is a sign pointing left, which reads "PROM"; on the right, there is a sign pointing right, which reads "LAN PARTY IN FORMAL ATTIRE".]


Finish Line

Explanation:
Cueball and Megan are playing Mario Kart , with Cueball's Luigi character ahead of Megan's Mario towards the end of the race. Megan begins waxing philosophically on how she sometimes stops right before the Finish line (hence the title), because she knows that she has already won and then does not need the machine to tell her so. She says it proves she doesn't  act like a rat going through a laboratory maze in pursuit of cheese.
This talk makes Cueball realize that winning a video game isn't really important, and how by speeding through a racing level like the game asks you to do, you sometimes miss the fun of simply exploring the level and enjoying the extraordinary level of detail and work that went into it. He thus exclaims that it was a good call and slows down - expecting Megan to join him exploring.
In the end, it was just a ruse by Megan, who speeds past him and wins, much to her glee. "It's more fun than a blue shell," she says, referring to the Mario Kart item that, when fired, will inevitably hit the race leader and cause him to crash. Randall has rather adamantly expressed his opinion about blue shells before in 290: Fucking Blue Shells .
Cueball's response suggests that he has been fooled before by Megan's Be a rebel speech - something she can pull off against him again and again. This leads to the subject of the title text.
Note: In MKWii, people sometimes troll others by stopping right at the finish line. When the person behind them gets close, they just cross the line and cause 2nd place to lose.
The title text refers to the comic strip Peanuts , and the running gag where fussbudget Lucy would hold an American football for lovable loser Charlie Brown , and he'd come running at it full speed, only to have Lucy pull the football away at the last moment and send Charlie Brown crashing to the ground. What made it funny was that each time, Lucy would find some way to convince Charlie Brown that this time, she wouldn't pull the football away, and he'd try again — but lo and behold, of course she did. (See example of this, in the collection of moments shown in the very last Peanuts comic ).
The title text asks the important question if Lucy believed the things she said - even if she would eventually pull the ball away. If so, it would be easier to fool Charlie Brown. Maybe Cueball suggests that Megan believes what she says up to the point where she wins....
[Luigi with green clothes in a green go-cart is clearly in the lead of a game of Mario Kart with Mario in red clothes in a red go-cart. Mario is so far behind that he seems much smaller. Two speech bubbles with arrows pointing at the two show what Megan and Cueball, shown later, say to each other.] Megan (playing Mario): Sometimes I stop right before the finish line. Cueball (playing Luigi): Why?
[A small square panel is inserted at the bottom of the first, crossing over the frame to the next panel and below the bottom of this panel. It shows Megan sitting on the floor leaning up against a coach while holding the game control in both hands looking at the large TV in front of her, only partly inside the frame. Her speech bubble is like the previous panel, pointing at her with an arrow, but most of the bubble is inside the first panel and also breaking into the next panel.] Megan: 'Cause I know I've won.
[Scene moved to look in from the direction of the TV at the couch. Cueball is sitting on the other end of the couch to the left holding his hands out to either side while looking down at Megan on the floor, who is still holding her remote in both hands playing the video game.] Megan: It proves I'm playing for fun, on my own terms. That I don't need validation from the machine. Megan: That I'm not a rat pulling a lever.
[Scene moved to the side, showing both the couch with Cueball in it holding his hands up, Megan in front on the floor working the remote and the entire TV. Speech from the TV is shown in a broken bubble.] Cueball: ...Man. Good Call. Let's stop and explore the course for a- Game: Player Two wins Cueball: Hey! Megan: Ha ha!
[Zoom in on the couch still from the side, Cueball leaning forward with the game control in his hand on the arm rest and Megan on the floor sitting more relaxed with the remote in one hand.] Cueball: Dammit, I'm a sucker for your "Be a Rebel" speech. Megan: It's more fun than a blue shell.


Security Holes

Explanation:
The "Debian-OpenSSL fiasco" was a major security problem discovered in the Debian Linux distribution and its version of the cryptographic library called OpenSSL . With just a tiny change in the software, which was intended to have no effect on security, its random number generator was completely crippled, as was the security of all cryptographic keys generated by the system. The problem was created when a Debian developer removed one line of code that was crucial, even though it could seem like it did nothing useful. More detail about the fiasco: Crippling Crypto: The Debian OpenSSL Debacle , Debian's information page about the problem .
The title text refers also to this issue: After the security problem was found, all cryptographic keys generated or used on the broken operating system needed to be replaced. Many systems introduced special checks for such weak keys, adding the keys to blacklists , thereby preventing their use and forcing users to create new keys. Randall claims that he was affected by that when uploading this comic to the server.
The panels on the left present Cueball as a programmer who, on a whim, removes pieces of code, ( commenting out the code by prepending the line with two slashes), presumably thinking that they are not necessary. The first removed line, MD_update(&m, buf, j); , is the exact piece of code that was removed in the Debian fiasco. The next panels show him commenting out fictitious lines of code apparently preventing bad things from happening.
The other part of the comic lists "security problems" that were allegedly discovered in other Linux variants afterwards:
Cryptographic software in Fedora Core was allegedly not secure against toy decoder rings . This is probably a reference to the association of the fedora with 1930s and 40s culture (especially gangsters and film noir ), and the contemporaneous introduction and popularity of toy decoder rings.
Xandros (used in Asus Eee PC netbooks) gave superuser privileges to anybody "if asked in a stern voice." This is likely a reference to the fact that the preinstalled Xandros OS did not require a password for root privileges by default.
Gentoo would succumb to flattery, which may be a reference to Gentoo's notorious difficulty to manage. Any user who is capable of understanding it might have a large ego, and therefore be susceptible to flattery.
OLPC OS could have been attacked using Jeff Goldblum 's laptop computer, which refers to a scene in the Independence Day movie , where Jeff Goldblum's character was able to hack into an alien spaceship using his Apple PowerBook computer - which is a topic of great contempt by geeks who point to the absurdity of such a construction.
Slackware gave superuser privileges to anybody who "says Elvish word for 'friend'," which refers to a scene in The Lord of the Rings , where the entrance door to Moria could have been opened using a password mellon , the Elvish word for "friend," as indicated on the door itself.
And Ubuntu , which is another Linux distribution, was allegedly found to be actually Windows Vista , the latest version of Microsoft Windows at this time in 2008. This may be a reference to Ubuntu being developed with non-advanced users in mind, with many fail-safes and additional features being turned on by default, which had more in common with Windows than any other Linux-based operating system at the time.
[Cueball sitting at computer.] Cueball: I'll just comment out these lines...
// MD_update(&m, buf, j);
// do_not_crash();
// prevent_911();
In the rush to clean up the debian-openssl fiasco, a number of other major security holes have been uncovered:
[A two-column table is shown:]
Affected System Security problem
Fedora Core Vulnerable to certain decoder rings
Xandros (EEE PC) Gives root access if asked in a stern voice
Gentoo Vulnerable to flattery
OLPC OS Vulnerable to Jeff Goldblum’s PowerBook
Slackware Gives root access if user says Elvish word for “friend”
Ubuntu Turns out distro is actually just Windows Vista with a few custom themes


Fortune Cookies

Explanation:
Fortune cookies are crisp cookies containing a small piece of paper with words of wisdom or a vague prophecy. Even though they were not actually invented in China, they are commonly served as dessert in Chinese restaurants in the United States.
There is a common joke involving fortune cookies that involves appending "in bed" — the phrase "in bed" being one of many sexual innuendo jokes along with " your mom ," "that's what she said," and " said the actress to the bishop " — to the end of the fortune, usually creating a sexual innuendo or other bizarre messages.
This comic turns that joke around, showing how appending "except in bed" can also create even more amusing messages.
The title text instead shows the example of an imaginary fortune that would not change in meaning if "in bed" was appended. The meaning would, however, change considerably if except in bed was added instead. A part of the joke is that you will never find such a fortune in a cookie!
[Megan to the left, Cueball to the right, and Blondie in the middle are sitting on chairs around a table with lots of small stuff on it. A few small white items are standing up. All three are reading from the piece of paper they each hold up in their hands (Megan only using one hand). Below them, there is a caption inside the panel.] Megan: "The ones you love will never let you down." Cueball: "Seek nonviolence in everything you do." Blondie: "Your self-confidence is well-placed."
Instead of "In bed", I've found that fortune cookies are often more improved by appending " Except in bed".


Geohashing

Explanation:
Geocaching is a sport where you have to find things hidden by other people based on geographical coordinates. Randall has had a similar idea before in 201: Christmas GPS .
Geohashing is a sport created by Randall based on reaching a random location determined by an algorithm that uses a hash function that involves the current date, location, and the Dow opening price. The Dow Jones Industrial Average is a stock market index dealt in New York City.
The algorithm is built in a way that:
The algorithm works as follows:
MD5 is a cryptographic hashing algorithm, and converts plaintext data into a seemingly random 128-bit (32 character) string. A good hashing algorithm should have three main properties: it is non-reversible, you cannot generate any plaintext data back from the hash, and a given sample of data will always produce the same hash value, but even a tiny change to the original plaintext should produce an entirely different hash.
The example co-ordinates are for the Google headquarters in California, as you can see here: 37.421542 -122.085589 . The example date, May 26 2005, may reference the fact that the first edition of the Dow came out on May 26, 1896. (Why 2005? Unclear.)
While geohashing was originally intended as a joke [ citation needed ] , there are people who geohash regularly. Please see the link to the Geohashing wiki above.
The title-text may imply that people should bring games to their geohashing location on the Saturday following the comic's release. If they do so and take photos, they may post them to https://geohashing.site/geohashing/games_we_play .
Date (example): 2005-05-26 That date's (or most recent) DOW opening: 10458.68 [Concatenate, with a hyphen: 2005-05-26-10458.68] md5: db9318c2259923d08b672cb305440f97 [Split it up into two pieces:] 0.db9318c2259923d0, 0.8b672cb305440f97 To decimal: 0.857713..., 0.544544... Your location (example): 37.421542, -122.085589 [Combine integer part of location with fractional part of hash:] Destination Coordinates: 37.857713, -122.544544 Sample Implementation: http://xkcd.com/geohashing/