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		<updated>2026-04-05T19:27:06Z</updated>
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	<entry>
		<id>https://www.explainxkcd.com/wiki/index.php?title=153:_Cryptography&amp;diff=78563</id>
		<title>153: Cryptography</title>
		<link rel="alternate" type="text/html" href="https://www.explainxkcd.com/wiki/index.php?title=153:_Cryptography&amp;diff=78563"/>
				<updated>2014-11-09T22:57:57Z</updated>
		
		<summary type="html">&lt;p&gt;Deny existence: /* Explanation */ –wrong word&lt;/p&gt;
&lt;hr /&gt;
&lt;div&gt;{{comic&lt;br /&gt;
| number    = 153&lt;br /&gt;
| date      = September 6, 2006&lt;br /&gt;
| title     = Cryptography&lt;br /&gt;
| image     = cryptography.png&lt;br /&gt;
| titletext = If you got a big keyspace, let me search it.&lt;br /&gt;
}}&lt;br /&gt;
&lt;br /&gt;
==Explanation==&lt;br /&gt;
This comic refers to the study of {{w|cryptography}}. We can note the presence of the {{w|International Association for Cryptologic Research|International Association for Cryptologic Research (IACR)}} logo in the podium, an association who organizes the most important conferences in the cryptology field. [[Cueball]], at the podium, is describing a proposed crypto system in which a computer program that turns a very large number, called the &amp;quot;{{w|key (cryptography)|key}}&amp;quot;, and a message into an encrypted form that can only be read by using the same key, based on the model of a {{w|Feistel cipher}}. Part of any Feistel cipher is the &amp;quot;round function&amp;quot;, which determines how the key is applied to the original message; this is applied multiple times with a variety of tricks and techniques to insure the process can eventually be reversed. One common component of round functions is the {{w|S-box}}, a simple table that converts input bytes into output bytes, preferably in a way that doesn't correspond to any mathematical rules.&lt;br /&gt;
&lt;br /&gt;
Here, the S-box would be implemented by doing the following (with the computer operation actually shown in the diagrams indicated in parentheses):&lt;br /&gt;
&lt;br /&gt;
#Take the bitstring down (roll right by 1)&lt;br /&gt;
#Flip it (take its binary NOT)&lt;br /&gt;
#Reverse it (run the bits in the opposite order)&lt;br /&gt;
&lt;br /&gt;
This would be run on each round of the cipher to further scramble the message for the next round. As the caption implies, the steps are based on a line from the {{w|Missy Elliott}} song ''{{w|Work It (Missy Elliott song)|Work It}}'': '''&amp;quot;I put my thing down, flip it and reverse it.&amp;quot;''' As with any encryption system there must be a way to decrypt the cipher text. In Missy Elliott's song, the phrase &amp;quot;I put my thing down, flip it and reverse it&amp;quot; is repeatedly played backward, sounding like gibberish. In the same way, steps to a feistel cipher based algorithm are executed in reverse to obtain the original plain text from a cipher text.&lt;br /&gt;
&lt;br /&gt;
The {{w|Key space (cryptography)|keyspace}} for a cryptographic algorithm is the number of possible keys the algorithm can possibly accept. For example, {{w|Advanced Encryption Standard|AES-256}} has a keyspace of 2&amp;lt;sup&amp;gt;256&amp;lt;/sup&amp;gt; (roughly 1.1579209e+77) possible keys, simply because the algorithm specifies that each key is 256 bits wide. The title text is referring to &amp;quot;searching a keyspace&amp;quot;, which is to say, simply trying every key until you find one that works. (For reference, a computer would require roughly the energy of a billion billion supernovas to even count to 2&amp;lt;sup&amp;gt;256&amp;lt;/sup&amp;gt;, let alone actually try each one.) The precise wording &amp;quot;If you got a big keyspace, let me search it&amp;quot; is, of course, another reference to the same song: &amp;quot;If you got a big **** let me search ya&amp;quot; (The word &amp;quot;penis&amp;quot; is censored by the trumpeting of an elephant).&lt;br /&gt;
&lt;br /&gt;
===Inside references and real life shenanigans===&lt;br /&gt;
&lt;br /&gt;
Cueball is banned from multiple conferences for similar pranks in [[541: TED Talk]]. In response to 541, {{w|PyCon}} organizers jokingly [http://pycon.blogspot.com/2009/02/randall-munroe.html announced] that Randall Munroe was banned from PyCon 2009 due to &amp;quot;last year's disgraceful keynote, 'Web Spiders vs. Red Spiders'.&amp;quot; They also said they instructed their volunteers to refuse admission to him and &amp;quot;any stick figures who may attempt to register, particularly if they are wearing hats.&amp;quot;&lt;br /&gt;
&lt;br /&gt;
Messages on the PyCon-Organizers mailing list show that this joke was intended to get Randall to come to PyCon: (The links will only work if you're subscribed to the mailing list.)&lt;br /&gt;
:PyCon mentioned briefly in today's xkcd:&lt;br /&gt;
:http://xkcd.com/541/&lt;br /&gt;
:We've still never gotten Randall Munroe to actually attend, have we? Anybody want to take charge of twisting his arm this time?  I think we can still offer him a &amp;quot;press pass&amp;quot; (free registration). [...] [http://mail.python.org/mailman/private/pycon-organizers/2009-February/011224.html]&lt;br /&gt;
::An invite would seem most appropriate given the cartoon. :-)&lt;br /&gt;
::We could also have an official PyCon blog post confirming his ban... [http://mail.python.org/mailman/private/pycon-organizers/2009-February/011225.html]&lt;br /&gt;
:::How about a public blog post LIFTING the ban and inviting him? [http://mail.python.org/mailman/private/pycon-organizers/2009-February/011226.html]&lt;br /&gt;
::::Confirming the ban is far funnier... He's definitely a disturbing influence on programmers. [http://mail.python.org/mailman/private/pycon-organizers/2009-February/011227.html]&lt;br /&gt;
:::::Agreed, especially if we invite him concurrently with confirming the ban. [http://mail.python.org/mailman/private/pycon-organizers/2009-February/011239.html]&lt;br /&gt;
:::::(a few posts later)&lt;br /&gt;
:::::I'm happy to participate in actually throwing some thin guy out of the conference, and then get some graphics savvy person to animate a stick figure over that. :) [...][http://mail.python.org/mailman/private/pycon-organizers/2009-February/011274.html]&lt;br /&gt;
::::::here's a rough idea of what would show up if you invited him to actually do any speaking...&lt;br /&gt;
::::::http://www.youtube.com/watch?v=zJOS0sV2a24&lt;br /&gt;
::::::it's fairly long. he shows up in the beginning around 3:25. [http://mail.python.org/mailman/private/pycon-organizers/2009-February/011275.html]&lt;br /&gt;
:::::::For the record, I did try to convince him to come when got the art for the tshirt last year.  He didn't seem super psyched, but then again emotions are hard to read via IRC.&lt;br /&gt;
:::::::I love the idea of &amp;quot;officially&amp;quot; banning him, however. ;-) [http://mail.python.org/mailman/private/pycon-organizers/2009-February/011241.html]&lt;br /&gt;
::::::::(a few posts later)&lt;br /&gt;
::::::::OK - posted to the PyCon blog, by the power vested in me as publicity chair.  With Michael Foord's excellent sentence added.&lt;br /&gt;
::::::::Now let him know that since he's banned, he HAS to come. [http://mail.python.org/mailman/private/pycon-organizers/2009-February/011251.html]&lt;br /&gt;
&lt;br /&gt;
==Transcript==&lt;br /&gt;
:[Cueball at a podium in front of a conference audience, with a poster beside him.]&lt;br /&gt;
:Cueball: My cryptosystem is like any Feistel cipher, except in the S-Boxes we simply take the bitstring down, flip it, and reverse it.&lt;br /&gt;
:&lt;br /&gt;
: [the poster reads:]&lt;br /&gt;
:: Decryption&lt;br /&gt;
:: &amp;lt;code&amp;gt;01101010&amp;lt;/code&amp;gt;&lt;br /&gt;
:: &amp;lt;code&amp;gt;&amp;amp;nbsp;&amp;amp;nbsp;&amp;amp;nbsp;&amp;gt;&amp;gt;&amp;lt;/code&amp;gt;&lt;br /&gt;
:: &amp;lt;code&amp;gt;00110101&amp;lt;/code&amp;gt;&lt;br /&gt;
:: [inverter symbol]&lt;br /&gt;
:: &amp;lt;code&amp;gt;11001010&amp;lt;/code&amp;gt;&lt;br /&gt;
:: [crossed arrows]&lt;br /&gt;
:: &amp;lt;code&amp;gt;01010011&amp;lt;/code&amp;gt;&lt;br /&gt;
:&lt;br /&gt;
:I've been barred from speaking at any major cryptography conferences ever since it became clear that all my algorithms were just thinly disguised Missy Elliott songs.&lt;br /&gt;
&lt;br /&gt;
{{comic discussion}}&lt;br /&gt;
[[Category:Comics featuring Cueball]]&lt;br /&gt;
[[Category:Public speaking]]&lt;br /&gt;
[[Category:Banned from conferences]]&lt;br /&gt;
[[Category:Cryptography]]&lt;/div&gt;</summary>
		<author><name>Deny existence</name></author>	</entry>

	<entry>
		<id>https://www.explainxkcd.com/wiki/index.php?title=141:_Parody_Week:_Achewood&amp;diff=78552</id>
		<title>141: Parody Week: Achewood</title>
		<link rel="alternate" type="text/html" href="https://www.explainxkcd.com/wiki/index.php?title=141:_Parody_Week:_Achewood&amp;diff=78552"/>
				<updated>2014-11-09T11:19:29Z</updated>
		
		<summary type="html">&lt;p&gt;Deny existence: gr., +missing whitespace&lt;/p&gt;
&lt;hr /&gt;
&lt;div&gt;{{comic&lt;br /&gt;
| number    = 141&lt;br /&gt;
| date      = August 14, 2006&lt;br /&gt;
| title     = Parody Week: Achewood&lt;br /&gt;
| image     = achewood.png&lt;br /&gt;
| titletext = I always wanted to impress them with how well I could hear, didn't you? Also, this sets the record for number of awkward-pause panels in one strip (previously held by Achewood)&lt;br /&gt;
}}&lt;br /&gt;
&lt;br /&gt;
==Explanation==&lt;br /&gt;
{{w|Achewood}} is a webcomic by {{w|Chris Onstad}}. It portrays the lives of a group of anthropomorphic stuffed toys, robots, and pets. The comic's humor is often lacking a traditional set punchline, and have many awkward pause panels. &lt;br /&gt;
&lt;br /&gt;
This comic has three of the prominent characters from the strip: Phillippe, Ray and Roast Beef. In the first panel, Phillippe is dreaming of having his ears checked. There's an eye chart on the wall behind him. The doctor informs him that because of his superhearing power he is needed at Hogwarts.&lt;br /&gt;
&lt;br /&gt;
Afterwards, the comic is a conversation between Roast Beef and Ray about Ray being invited to participate in what seem to be a talent show, with no reference to Phillippe again before the title-text.&lt;br /&gt;
&lt;br /&gt;
The comic is written well in the style of Onstad and his humor is in the parody. The last 11 panels are having no dialogues which is also in style of Achewood although '11' is a tad too far at poking fun at it.&lt;br /&gt;
&lt;br /&gt;
Sweet Sweetback's Badasssss Song is a 1971  [[Blaxploitation]]film that is generally regarded as an examplar of the genre.&lt;br /&gt;
&lt;br /&gt;
At the title text [[Randall]] claims that he set a new record on awkward-pause panels.&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
This comic is a part of the Parody Week, just joking about other webcomics.&lt;br /&gt;
*'''Parody Week: Achewood'''&lt;br /&gt;
*[[Parody Week: Megatokyo]]&lt;br /&gt;
*[[Parody Week: TFD and Natalie Dee]]&lt;br /&gt;
*[[Parody Week: A Softer World]]&lt;br /&gt;
*[[Parody Week: Dinosaur Comics]]&lt;br /&gt;
&lt;br /&gt;
==Transcript==&lt;br /&gt;
:Doctor (out of frame): Philippe, your hearing is perfect! In fact, you heard ALL the beeps! You have super-hearing! You're needed at Hogwarts!&lt;br /&gt;
:Philippe: Oh boy!&lt;br /&gt;
:Meanwhile ...&lt;br /&gt;
:Ray: Beef, check this out. I got an invite to that The Dude Is Pretty Awesome In Most Measurable Ways I Mean Wow competition.&lt;br /&gt;
:Beef: Alright that is pretty sweet dogg what is your strategy gonna consist of&lt;br /&gt;
:Ray: I'm thinkin' I need to point out my best features--maybe go holdin' a sign with an arrow toward my junk.&lt;br /&gt;
:[A panel with Ray holding a sign with &amp;quot;Yes.&amp;quot; in bold text and an arrow pointing down and across.]&lt;br /&gt;
:Beef: Yeah well I always said subtlety was your middle name dogg&lt;br /&gt;
:Beef: And also your first and last in case they didn't get the point&lt;br /&gt;
:Ray: How do you think I should play it?&lt;br /&gt;
:Beef: Well basically you got no chance as I see it these dudes are all lovers and fighters to the last&lt;br /&gt;
:Beef: All sprung fully formed from the head of Sweet Sweetback&lt;br /&gt;
:Beef: You are gonna stand out as the sort of dude who stays at home all night playing fleshlight tag&lt;br /&gt;
:Ray: These words you got are crazy. Didn't I win the outdoor fight?&lt;br /&gt;
:Beef: Uh huh about the fight I wasn't gonna tell you but how could you miss that I was setting you up&lt;br /&gt;
:Ray: What?&lt;br /&gt;
:Beef: You got played dogg&lt;br /&gt;
:Beef: I basically just didn't have the heart to go through with it in the end.&lt;br /&gt;
:Beef: Anyway the point is that you are gonna lose this thing so hard&lt;br /&gt;
:Beef: All cheap McD's hamburger to their slabs of steak&lt;br /&gt;
:Beef: A couple 12-oz sirloins garnished with nothing but pure manhood&lt;br /&gt;
:Beef: Maybe some sprigs of parsley&lt;br /&gt;
:Beef: You are pretty much going down&lt;br /&gt;
:[Closeup of a shocked Ray.]&lt;br /&gt;
:[Silence.]&lt;br /&gt;
:[Silence. Beef looks perturbed and his ear is twitching. Ray's mouth is open.]&lt;br /&gt;
:[Silence. Beef looks sorry.]&lt;br /&gt;
:[Silence. Beef looks sorry and Ray looks annoyed.]&lt;br /&gt;
:[Silence.]&lt;br /&gt;
:[Silence.]&lt;br /&gt;
:[Silence. Beef is looking down and Ray's mouth is open.]&lt;br /&gt;
:[Silence.]&lt;br /&gt;
:[Silence. Beef is looking down and Ray's mouth is open.]&lt;br /&gt;
:[Silence. Beef looks surprised.]&lt;br /&gt;
&lt;br /&gt;
==Trivia==&lt;br /&gt;
*According to [[Randall]], it also mildly references to {{w|Athena#Birth|The birth of Greek Goddess Athena}}.&lt;br /&gt;
&lt;br /&gt;
{{comic discussion}}&lt;/div&gt;</summary>
		<author><name>Deny existence</name></author>	</entry>

	<entry>
		<id>https://www.explainxkcd.com/wiki/index.php?title=140:_Delicious&amp;diff=78543</id>
		<title>140: Delicious</title>
		<link rel="alternate" type="text/html" href="https://www.explainxkcd.com/wiki/index.php?title=140:_Delicious&amp;diff=78543"/>
				<updated>2014-11-09T01:46:03Z</updated>
		
		<summary type="html">&lt;p&gt;Deny existence: typograph. corr.&lt;/p&gt;
&lt;hr /&gt;
&lt;div&gt;{{comic&lt;br /&gt;
| number    = 140&lt;br /&gt;
| date      = August 11, 2006&lt;br /&gt;
| title     = Delicious&lt;br /&gt;
| image     = delicious.png&lt;br /&gt;
| titletext = I'm currently in the I Have Cheese phase of this cycle.&lt;br /&gt;
}}&lt;br /&gt;
&lt;br /&gt;
==Explanation==&lt;br /&gt;
The simplest explanation for the comic is the recipe for nachos. You take some tortilla chips, spread them out on a plate, sprinkle them with grated cheese and perhaps some other ingredients like salsa, beans, or guacamole, and put the plate in the oven until the cheese is melted. As usual with a full bag of snacks, you always end up with that tiny bit left at the bottom of the bag. In this case, it is either leftover grated cheese (left) or tortilla chips (right). So you end up buying another package of the other ingredient to make nachos again.&lt;br /&gt;
&lt;br /&gt;
The lower caption is a play on the words {{w|Virtuous circle and vicious circle|vicious cycle}}, in which a negative feedback loop reinforces itself — in contrast to a ''virtuous cycle'' in which a positive feedback loop is established.&lt;br /&gt;
&lt;br /&gt;
==Transcript==&lt;br /&gt;
:[Frame is split by a diagonal.]&lt;br /&gt;
:[First half: Cueball in front of open fridge.]&lt;br /&gt;
:Cueball: I have leftover cheese. I should get chips and make nachos.&lt;br /&gt;
&lt;br /&gt;
:[Second half: Cueball with bag of chips.]&lt;br /&gt;
:Cueball: I have leftover chips. I should get cheese and make nachos.&lt;br /&gt;
&lt;br /&gt;
:A delicious cycle&lt;br /&gt;
&lt;br /&gt;
{{comic discussion}}&lt;br /&gt;
[[Category:Comics featuring Cueball]]&lt;/div&gt;</summary>
		<author><name>Deny existence</name></author>	</entry>

	<entry>
		<id>https://www.explainxkcd.com/wiki/index.php?title=129:_Content_Protection&amp;diff=78526</id>
		<title>129: Content Protection</title>
		<link rel="alternate" type="text/html" href="https://www.explainxkcd.com/wiki/index.php?title=129:_Content_Protection&amp;diff=78526"/>
				<updated>2014-11-08T17:39:50Z</updated>
		
		<summary type="html">&lt;p&gt;Deny existence: source code embellishment, gr.&lt;/p&gt;
&lt;hr /&gt;
&lt;div&gt;{{comic&lt;br /&gt;
| number    = 129&lt;br /&gt;
| date      = July 17, 2006&lt;br /&gt;
| title     = Content Protection&lt;br /&gt;
| image     = content protection.png&lt;br /&gt;
| titletext = If you think the purveyors of DRM simply want to protect artists, check out chapters 13 and 14 in Free Culture, by Lawrence Lessig. Their goal is the elimination of all culture they don't control.&lt;br /&gt;
}}&lt;br /&gt;
&lt;br /&gt;
==Explanation==&lt;br /&gt;
&lt;br /&gt;
This comic is a commentary on {{w|HDCP}}, a media standard which requires all the devices from player to cable to display to be &amp;quot;approved&amp;quot; to carry HDCP content. HDCP is intended to protect media encrypted with {{w|Digital rights management|DRM}} from being intercepted between the player and the display. Interestingly, however, it is literally impossible for DRM advocates to completely prevent copying (even with such drastic measures) because of the {{w|analog hole}}: since the content must be shown in a human-perceptible form, it can be captured by analog means, such as recording the display with a video camera.&lt;br /&gt;
&lt;br /&gt;
In addition to illustrating the absurdity of HDCP, the comic presents the darker idea that when your devices control what information you are exposed to, the controlling companies can act as &amp;quot;{{w|thought police}}&amp;quot; and ensure that your mind only contains &amp;quot;approved content&amp;quot;.&lt;br /&gt;
&lt;br /&gt;
With the title text [[Randall]] is referring again to {{w|Digital rights management|DRM}}. The {{w|Students for Free Culture|Free Culture}} movement ({{w|Lawrence Lessig}} being one of their activists) is fighting for free content. DRM advocates claim that their technology &amp;quot;protects&amp;quot; artists by preventing piracy, while in reality DRM is more effective as a means of giving media companies control over devices than it is at preventing piracy.&lt;br /&gt;
&lt;br /&gt;
==Transcript==&lt;br /&gt;
:Content Protection System:&lt;br /&gt;
:[Megan sits on a couch watching a large flat-panel television, connected to a box labeled HDMI.&lt;br /&gt;
:The screen is labeled with &amp;quot;Approved screen&amp;quot;&lt;br /&gt;
:The cable is labeled with &amp;quot;Approved connection&amp;quot;&lt;br /&gt;
:The HDMI box is labeled with &amp;quot;Approved player&amp;quot;&lt;br /&gt;
:Megan's head is labeled with &amp;quot;Approved content&amp;quot;.]&lt;br /&gt;
&lt;br /&gt;
{{comic discussion}}&lt;br /&gt;
[[Category:Comics featuring Megan]]&lt;/div&gt;</summary>
		<author><name>Deny existence</name></author>	</entry>

	<entry>
		<id>https://www.explainxkcd.com/wiki/index.php?title=123:_Centrifugal_Force&amp;diff=78517</id>
		<title>123: Centrifugal Force</title>
		<link rel="alternate" type="text/html" href="https://www.explainxkcd.com/wiki/index.php?title=123:_Centrifugal_Force&amp;diff=78517"/>
				<updated>2014-11-08T11:53:38Z</updated>
		
		<summary type="html">&lt;p&gt;Deny existence: source code embellishment, gr., +Wikipedia link&lt;/p&gt;
&lt;hr /&gt;
&lt;div&gt;{{comic&lt;br /&gt;
| number    = 123&lt;br /&gt;
| date      = July 3, 2006&lt;br /&gt;
| title     = Centrifugal Force&lt;br /&gt;
| image     = centrifugal force.png&lt;br /&gt;
| titletext = You spin me right round baby, right round, in a manner depriving me of an inertial reference frame. Baby.&lt;br /&gt;
}}&lt;br /&gt;
&lt;br /&gt;
==Explanation==&lt;br /&gt;
[[Black Hat]] has strapped {{w|James Bond}} to a centrifuge and claims the {{w|Centrifugal force|centrifugal}} force will be lethal. Bond objects that there is no such thing, but just {{w|Centripetal force|centripetal}} force. The notion of centrifugal force is a common one, as we experience it whenever we turn. Teachers will initially teach Newtonian mechanics in an inertial frame, and in inertial frames the centrifugal force is zero. Instead, a body that moves in a circle does so because of a centripetal force (acting towards the centre of the rotation). This is a reasonable, and correct view, but is a subtle point that many students find hard to grasp as it seems to contradict their personal experience of centrifugal forces. For the sake of exposition, teachers may claim that &amp;quot;There is no such thing as centrifugal force&amp;quot;. This however is also a misconception which is addressed in the explanation below:&lt;br /&gt;
;Observers' point of view (Black Hat, us, etc.)&lt;br /&gt;
:James Bond is moving in a circle, and is therefore accelerating. The force keeping him there is an inward force of contact against the centrifuge, a centripetal force. Via Newton's {{w|Newton's laws of motion#Newton's third law|third law}}, since the centrifuge is pushing Bond inward, Bond is pushing the centrifuge outward. The centrifuge's material is strong enough not to break under this force, however.&lt;br /&gt;
;James Bond's point of view&lt;br /&gt;
:In James Bond's frame of reference, Bond is at rest. He is kept there by two forces: the above-mentioned inward force of contact against the centrifuge, and an ''outward centrifugal force''. He feels both forces.&lt;br /&gt;
&lt;br /&gt;
As mentioned in the explanation, as the centrifuge rotates faster, the forces needed to keep him in motion get larger, so the force he feels gets larger. This will eventually kill him. The conclusion will be the same regardless of which frame of reference is chosen.&lt;br /&gt;
&lt;br /&gt;
Teachers of mechanics are well aware of this, however in introductory expositions these ideas are often not taught. In theoretical mechanics, one describes the positions and velocities of the particles in a model relative to a frame of reference. This means that a time is chosen to be time 0, and positions are chosen to be (0,0,0), (1,0,0), (0,1,0) and (0,0,1). With these chosen, the position and time of any particle in the system can be described. It is an axiom of Newtonian Mechanics that there exist &amp;quot;Inertial Frames&amp;quot;. In an inertial frame a particle will remain at rest or at a constant speed unless acted on by an external force, and Newton's second law takes a simple form: F=ma. The surface of the Earth approximates an inertial frame. In a non-inertial frame, such as one rotating with a giant centrifuge, or moving with an accelerating vehicle, a particle will accelerate, relative to the frame. Newton's second law, when formed in such a frame is much more complicated, as it has terms for the linear acceleration of the frame, the angular acceleration of the frame, the centrifugal force and the {{w|Coriolis force}}. These extra terms are sometimes called &amp;quot;fictitious forces&amp;quot; as they result not from the choice of the frame of reference. The mathematics required to describe problems in a non-inertial frame is more sophisticated, and all problems may be solved using an inertial frame. Thus is reasonable that teachers at school level &amp;quot;lie to children&amp;quot; and teach the mechanics in inertial frames.&lt;br /&gt;
 &lt;br /&gt;
The final statement by Black Hat is that said by {{w|Auric Goldfinger}} in {{w|Goldfinger (film)|Goldfinger}} in response to James Bond's question &amp;quot;Do you expect me to talk?&amp;quot;&lt;br /&gt;
&lt;br /&gt;
The title text is inspired by {{w|Dead or Alive (band)|Dead or Alive's}} famous song from 1985, &amp;quot;{{w|You Spin Me Round (Like a Record)|You Spin Me Round}}&amp;quot;.&lt;br /&gt;
&lt;br /&gt;
==Transcript==&lt;br /&gt;
:[James Bond is strapped to a giant wheel suspended from the ceiling. Black Hat is standing next to two levers.]&lt;br /&gt;
:Black hat: How do you like my centrifuge, mister Bond? When I throw this lever, you will feel centrifugal force crush every bone in your body.&lt;br /&gt;
:[Same scene, but a closer shot.]&lt;br /&gt;
:Bond: You mean centripetal force. There's no such thing as centrifugal force.&lt;br /&gt;
:Black hat: A laughable claim, mister Bond, perpetuated by overzealous teachers of science. Simply construct Newton's laws in a rotating system and you will see a centrifugal force term appear as plain as day.&lt;br /&gt;
:[Closer shot, only Bond's head is visible.]&lt;br /&gt;
:Bond: Come now, do you really expect me to do coordinate substitution in my head while strapped to a centrifuge?&lt;br /&gt;
:Black hat: No, mister Bond. I expect you to die.&lt;br /&gt;
{{comic discussion}} &lt;br /&gt;
[[Category:Comics featuring Black Hat]]&lt;br /&gt;
[[Category:Physics]]&lt;/div&gt;</summary>
		<author><name>Deny existence</name></author>	</entry>

	<entry>
		<id>https://www.explainxkcd.com/wiki/index.php?title=117:_Pong&amp;diff=78514</id>
		<title>117: Pong</title>
		<link rel="alternate" type="text/html" href="https://www.explainxkcd.com/wiki/index.php?title=117:_Pong&amp;diff=78514"/>
				<updated>2014-11-08T07:33:38Z</updated>
		
		<summary type="html">&lt;p&gt;Deny existence: /* Explanation */ +Wikipedia-Link&lt;/p&gt;
&lt;hr /&gt;
&lt;div&gt;{{comic&lt;br /&gt;
| number    = 117&lt;br /&gt;
| date      = June 19, 2006&lt;br /&gt;
| title     = Pong&lt;br /&gt;
| image     = pong.png&lt;br /&gt;
| titletext = Following this, the pong paddle went on a mission to destroy Atari headquarters and, due to a mixup, found himself inside the game The Matrix Reloaded. Boy, was THAT ever hard to explain to him.&lt;br /&gt;
}}&lt;br /&gt;
&lt;br /&gt;
== Explanation ==&lt;br /&gt;
This comic largely refers to the 1999 movie ''{{w|The Matrix}}'', which is about escaping a simulated reality. In the movie a hacker called {{w|Neo (The Matrix)|Neo}} realizes that the world he lives in is fake, and that, like every other human, he is used as a slave battery by machines which, to keep them under control, make them feel like they're &amp;quot;living&amp;quot; in what is actually a computer-generated simulation of the world, called the &amp;quot;Matrix&amp;quot;. Upon discovery, Neo rebels to this misuse of mankind, and trains himself to interact with the computers that run the world until, being &amp;quot;the One&amp;quot; mentioned by a prophecy, he is able to control and use them to his own advantage. He takes part in a series of missions against those machines which wanted to keep the humans trapped in a simulated environment.&lt;br /&gt;
&lt;br /&gt;
In {{w|Pong}}, one of the earliest video games, one can play virtual table tennis against the computer. A ball (the tiny block) is &amp;quot;hit&amp;quot; by a paddle (the long block) and crosses over the screen, to be &amp;quot;hit&amp;quot; again by the other paddle. Failure to return the ball results in a point won by the opponent. The speed of the ball increases as the ralley runs longer.&lt;br /&gt;
&lt;br /&gt;
The two game programmers in the first frame apply Neo's story to the {{w|Artificial intelligence|AI}} bots they create to serve as computer players in their video games: what if one of them learns enough to become sentient, and understands the environment the programmers trapped it in? The outcome is shown: the paddle bot, understanding the game and realizing it is &amp;quot;the One&amp;quot;, takes control of the code of Pong to make the ball stop and drop. The same thing happens in the movie, where Neo, by &amp;quot;seeing through the code&amp;quot;, is able to stop bullets fired at him, and simply let them drop on the floor.&lt;br /&gt;
&lt;br /&gt;
In the image text, we learn that after increasing in intelligence, the &amp;quot;paddle&amp;quot; went on to destroy the headquarters of {{w|Atari}}, the producer of Pong which &amp;quot;trapped&amp;quot; the paddle into the game, much like Neo sought to destroy the machines to free the humans. In the process, the paddle ended up inside the game ''{{w|Enter the Matrix}}'' (a video game produced with ''{{w|The Matrix Reloaded}}'', a sequel to ''The Matrix''), also published by Atari. Since the whole premise of The Matrix is that everyone is trapped in virtual reality, the paddle now found itself in a second level of virtual reality, which could be pretty hard to comprehend.&lt;br /&gt;
&lt;br /&gt;
==Transcript==&lt;br /&gt;
:Cueball: So what do we do if video game AI opponents become smart enough to question the &amp;quot;Matrix&amp;quot; into which we've put them?&lt;br /&gt;
:Pong paddle: Wait a minute! None of this is real! I can see through the world! I can see the code! I AM THE ONE!&lt;br /&gt;
:[The pong ball is moving towards the paddle.]&lt;br /&gt;
:[The pong ball slows down.]&lt;br /&gt;
:[The pong ball stops in midair.]&lt;br /&gt;
:[The pong ball drops towards the bottom of the screen.]&lt;br /&gt;
{{comic discussion}}&lt;br /&gt;
[[Category:Comics featuring Cueball]]&lt;br /&gt;
[[Category:Comics with color]]&lt;br /&gt;
[[Category:Video games]]&lt;br /&gt;
[[Category:The Matrix]]&lt;/div&gt;</summary>
		<author><name>Deny existence</name></author>	</entry>

	<entry>
		<id>https://www.explainxkcd.com/wiki/index.php?title=98:_Fall_Apart&amp;diff=78400</id>
		<title>98: Fall Apart</title>
		<link rel="alternate" type="text/html" href="https://www.explainxkcd.com/wiki/index.php?title=98:_Fall_Apart&amp;diff=78400"/>
				<updated>2014-11-06T16:32:25Z</updated>
		
		<summary type="html">&lt;p&gt;Deny existence: source code embellishment&lt;/p&gt;
&lt;hr /&gt;
&lt;div&gt;{{comic&lt;br /&gt;
| number    = 98&lt;br /&gt;
| date      = May 5, 2006&lt;br /&gt;
| title     = Fall Apart&lt;br /&gt;
| image     = fall_apart.jpg&lt;br /&gt;
| titletext = #pugglewumper Tashari got me some ink pens! I've been experimenting with them.&lt;br /&gt;
}}&lt;br /&gt;
&lt;br /&gt;
==Explanation==&lt;br /&gt;
Despite [[Randall]] being enthusiastic about receiving ink pens, his first experiment with them has resulted in a rather bleak comic.&lt;br /&gt;
&lt;br /&gt;
Instead of multiple panels, the entire comic is a single drawing, but as we travel down the page, there is an apparent passage of time or, unless a better phrase can be found, the degree of falling apart.&lt;br /&gt;
&lt;br /&gt;
The comic seems to be expressing what it feels like when a relationship falls apart, and one of the implications is that the process cannot easily be reversed. At the top of the page, we see some people standing alone, apparently happy enough, and a couple. As we descend the page, we see examples of a couple split by a narrow chasm, someone isolated and alone on their own world fragment, a couple desperately trying to hang on to eachother, and a single figure falling chaotically and without control.  &lt;br /&gt;
&lt;br /&gt;
This figures are on a comic, and the representation is of what happens when their world — the page — literally falls apart. The implication is that this matches the actual feelings of people going through relationship breakups. In short, it is catastrophic.&lt;br /&gt;
&lt;br /&gt;
The identity of '#pugglewumper Tashari', the supplier of the pens, is not known. Judging by the use of the {{w|hashtag}}, it is someone with whom Randall communicates in {{w|IRC}}. In fact, 'pugglewump' appears to be an IRC channel. Although hashtags later came to be strongly associated with {{w|Twitter}}, this was not true at the time the comic was drawn.&lt;br /&gt;
&lt;br /&gt;
==Transcript==&lt;br /&gt;
:[Various people struggle as the comic disintegrates. Toward the top, people are standing calmly, some holding hands. As the parts of the comic break apart, people try to reach for each other, hold parts together, or curl up into a ball. By the bottom, a person is falling, surrounded by pieces of the comic.]&lt;br /&gt;
&lt;br /&gt;
{{comic discussion}}&lt;br /&gt;
[[Category:Comics featuring Cueball]]&lt;br /&gt;
[[Category:Comics featuring Megan]]&lt;br /&gt;
[[Category:Romance]]&lt;/div&gt;</summary>
		<author><name>Deny existence</name></author>	</entry>

	<entry>
		<id>https://www.explainxkcd.com/wiki/index.php?title=78:_Garfield&amp;diff=78160</id>
		<title>78: Garfield</title>
		<link rel="alternate" type="text/html" href="https://www.explainxkcd.com/wiki/index.php?title=78:_Garfield&amp;diff=78160"/>
				<updated>2014-11-02T13:46:30Z</updated>
		
		<summary type="html">&lt;p&gt;Deny existence: /* Explanation */ typograph. corr., punctuation&lt;/p&gt;
&lt;hr /&gt;
&lt;div&gt;{{comic&lt;br /&gt;
| number    = 78&lt;br /&gt;
| date      = March 20, 2006&lt;br /&gt;
| title     = Garfield&lt;br /&gt;
| image     = garfield.jpg&lt;br /&gt;
| titletext = The use of the 'Garfield' character for the purposes of this parody qualifies as fair use under the Copyright Act of 1976, 17 U.S.C. sec. 107. See Campbell v. Acuff-Rose Music (92-1292), 510 U.S. 569&lt;br /&gt;
}}&lt;br /&gt;
&lt;br /&gt;
==Explanation==&lt;br /&gt;
The newspaper comic strip {{w|Garfield}} has increasingly been known for repetitive, quality-lacking strips. This is partly because the creator, {{w|Jim Davis}}, prefers to explore the same subjects he is comfortable with but in different ways — or from a less charitable view, because the strip is intended for a wide audience and thus becomes homogenized and inoffensive by nature. Either way, these strips are now {{w|Ghostwriter|ghost written}} with little input from Davis, and rarely explore the unconventional. The comic is challenging Davis to do something unexpected and surprise us all. The comic also accuses Davis of being a &amp;quot;sell out&amp;quot;, sticking to bourgeois/commercial logic, something that dadaist artists challenged.&lt;br /&gt;
&lt;br /&gt;
{{w|Dadaism}} was an artistic movement in the early 20th century marked primarily by chaos, irrationality and surrealism. Some of the artists believed that the bourgeois logic made human beings unhappy and therefore led to war.&lt;br /&gt;
&lt;br /&gt;
Randall leads by example by featuring a strip that copies the style of Garfield, with multiple colors (xkcd usually contains only black and white, with some few containing an additional color like red or yellow) and a character that is not a stick figure breaking the normal xkcd pattern. Another dadaist aspect is the fact the while Garfield is smiling, he is communicating something that could be considered terrifying.&lt;br /&gt;
&lt;br /&gt;
The title text explains that xkcd is exercising legal use of Davis's intellectual property, namely the title character of his comic. The Supreme Court case mentioned, {{w|Campbell v. Acuff-Rose Music}}, confirmed that parody is legal even when there is commercial gain as a result, and also referenced the {{w|Copyright Act of 1976}}, 17 U.S.C. § 107, for the same reason.&lt;br /&gt;
&lt;br /&gt;
While this is normally understood by most anyone that questions such matters, [[Randall]] includes it as a reference to the lessening of strict copyright law, which many comics also mention, usually in the context of {{w|open-source software}} and those who promote it, like at the comics featuring [[:Category:Comics featuring Richard Stallman|Richard Stallman]].&lt;br /&gt;
&lt;br /&gt;
==Trivia==&lt;br /&gt;
The comic number, #78, corresponds to the year Garfield debuted, 1978.&lt;br /&gt;
&lt;br /&gt;
==Transcript==&lt;br /&gt;
:I want to see something unexpected in comics. Just one strip could make up for it all.&lt;br /&gt;
:[Garfield is standing on hind legs facing and looking directly at the camera. But is off-center in the frame, about 1/3 from the left, rotated very slightly clockwise.]&lt;br /&gt;
:[Zoom in on Garfield, still to the left, now rotated slightly counterclockwise.]&lt;br /&gt;
:[Zoom in again on Garfield, now the frame clips off the left side of his face.]&lt;br /&gt;
:Garfield thought bubble: The world is burning.&lt;br /&gt;
:[Final zoom in, the frame is ripped like a page, offset, and Garfield's eyes are half closed on the right half.]&lt;br /&gt;
:Garfield thought bubble: Run.&lt;br /&gt;
:Jim Davis, throw off your commercial shackles. Challenge us. Go out in a blaze of Dadaist glory. There is still time.&lt;br /&gt;
&lt;br /&gt;
{{comic discussion}}&lt;br /&gt;
[[Category:Comics with color]]&lt;/div&gt;</summary>
		<author><name>Deny existence</name></author>	</entry>

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