explain xkcd - User contributions [en]

3033: Origami Black Hole

2025-01-04T18:55:46Z

141.101.98.191: if can be created

{{comic
| number = 3033
| date = January 3, 2025
| title = Origami Black Hole
| image = origami_black_hole_2x.png
| imagesize = 272x480px
| noexpand = true
| titletext = You may notice the first half of these instructions are similar to the instructions for a working nuclear fusion device. After the first few dozen steps, be sure to press down firmly and fold quickly to overcome fusion pressure.
}}

==Explanation==
{{incomplete|Created by a PLANET-SIZED SWARM OF SELF-REPLICATING NUCLEAR POWERED PAPER COMPRESSION ROBOTS - Please change this comment when editing this page. It needs an explanation for the title text. Do NOT delete this tag too soon.}}

This comic shows what at first appears to be an actual page of {{w|origami}} directions, like [https://origami.me/crane/ this one] or [https://origami.guide/origami-animals/origami-rabbits/origami-sleeping-rabbit/ this one], except labeled "How to fold a real origami black hole". The "real" part may be referring to a "fake" origami black hole which would be a piece of origami made to look like a black hole (whatever that means). It seems black-hole-like origami does exist, as created by [https://parchmentandallthingspaper.wordpress.com/2011/11/16/folding/ Richard Sweeney]. The implication is that while the linked origami only resembles a black hole, Randall's instructions indicate a method to physically create a {{w|black hole}} out of origami paper. However, it quickly devolves into nothing other than repeating folds in half. This wouldn't really create a black hole unless one somehow additionally compressed the paper commensurate with its decrease in width and length as alluded to in the title text. Ordinarily it would become impossible long before the 190 folds in half that the instructions require. In fact - assuming a thickness of around 0.1mm the sum of the lengths and width of the paper would need to be around 10^110 meters for it to be possible to fold it 190 times.

The {{w|mathematics of paper folding}} were augmented with [https://web.archive.org/web/20051102085038/http://pomonahistorical.org/12times.htm work by a California high school student in 2001] who wrote equations that [https://web.archive.org/web/20211116013626/http://teachersofindia.org/sites/default/files/folding_paper_in_half.pdf related the size of paper to the maximum number of folds it could make], which has not yet exceeded the low teens in human competition. This could be exceeded by scoring the paper to cut and flatten the outer layers of the folds, but its thickness would immediately surpass its length, and compressing it beyond the size of its fibers would require some way to hold it together.

This comic is likely a reference to the {{w|Schwarzschild radius}} of a piece of paper. The Schwarzchild radius is a characteristic of every object that depends on the object's mass. If an object is compressed into the volume of a sphere with its characteristic Schwarzschild radius, then that object will become a black hole. (More specifically, it will become a {{w|Schwarzschild metric|Schwarzschild black hole}}.) As such, if a piece of paper were folded sufficiently many times so as to fit within its own Schwarzschild radius, it would become a black hole. However, this would require compressing the paper into a flat sheet at every step, otherwise the paper would have a thickness greatly exceeding its Schwarzschild radius.

If we assume standard {{w|origami paper#Kami|kami origami paper}} with a side length of 15cm and a weight of 70 grams per square meter, we get a Schwarzschild radius of 2.339×10^-30 meters corresponding to a mass of 1.575 grams. It follows that, ignoring the paper's thickness, we would need to halve each side length -log<sub>2</sub>((2×2.339×10<sup>-30</sup>)/0.15)=94.69 times to fit each side length within the "Schwarzschild diameter" of the paper. Using the square folding technique in the comic, this would take approximately 95*2=190 steps to complete, the exact number given in the comic.
Note that the radius of the resulting black hole is 15 orders of magnitude smaller than the {{w|Proton#Charge_radius|charge radius of a proton}}. {{w|Micro black holes|Black holes this small}}, if they can be created at all, are believed to quickly disintegrate by losing energy by {{w|Hawking radiation}}, but this has yet to be proved.

In actual fact, it's not possible to fold a piece of paper this many times, because the amount of paper 'wasted' in each fold [https://web.archive.org/web/20211116013626/http://teachersofindia.org/sites/default/files/folding_paper_in_half.pdf will quickly surpass the length and width of the paper]. For an ordinary letter-sized sheet (A4 or 8.5x11) the maximum number of folds is 7. The [https://www.guinnessworldrecords.com/world-records/494571-most-times-to-fold-a-piece-of-paper world record] for the total number of folds is 12, done with a length of tissue paper 3/4 mile (4000ft, 1219m) long. A group of MIT students demonstrated 13 folds using multiple miles of paper, but had to lay separate pieces together as it made them too thick to tape them. Materials other than paper, such as thin foil, can be folded more times. Not only that but, as the title text alludes to, prior to reaching any creation of a black hole, the pressures generated by the resulting {{w|Nuclear fusion#Confinement in thermonuclear fusion|fusion of its atoms}} must be overcome. Electron and neutron degeneracy pressure would also have to be overcome.

==Transcript==
{{incomplete transcript|Do NOT delete this tag too soon.}}

:How to fold a '''''real''''' origami black hole:

:Step 1.
:[A square sheet of paper shown folded in half, with a dashed line going across the middle, and an arrow pointing from one half to the other.]

:[In each step from Step 2. to Step 9., the paper is shown folded in half again and depicted in the same manner as Step 1. The aspect ratio of the sides alternates between 2:1 and 1:1.]
:Step 2.
:Step 3.
:Step 4.
:Step 5.
:Step 6.
:Step 7.
:Step 8.
:Step 9.

:Steps 10-189.
:[Text shown between tall square brackets:]
:Fold paper in half another 180 or so times.

:Step 190.
:[A labeled arrow points to a dot]
:Black hole!

{{comic discussion}}

[[Category:Physics]]

1537: Types

2015-06-13T08:31:01Z

141.101.98.191: /* Explanation */

{{comic
| number = 1537
| date = June 12, 2015
| title = Types
| image = types.png
| titletext = colors.rgb("blue") yields "#0000FF". colors.rgb("yellowish blue") yields NaN. colors.sort() yields "rainbow"
}}

==Explanation==
{{incomplete|Title text not explained. More details before the list.}}

This comic is a series of programming jokes about a ridiculous new programming language, perhaps inspired by [https://www.destroyallsoftware.com/talks/wat Gary Bernhardt's CodeMash 2012 lightning talk] on JavaScript's unpredictable typing. In the talk, the (highly technical) audience was unable to correctly guess the results of adding various JavaScript types and roared with laughter when they were revealed. The programming language shown in this comic has types even more unpredictable than JavaScript.

Most regular programming languages distinguish a number of types, e.g. integers, strings, lists … all of which have different behaviours. The operation "+" is conventionally defined over more than one of these types. Applied to two integers, it returns their addition; applied to two strings (denoted by being enclosed in quotes) it concatenates them:

<code>> 2 + 3

5

> "123" + "abc"

"123abc"</code>

While these behaviours are standard, conventional, and intuitive, there is a huge amount of variation among programming languages when you apply an operation like "+" to different types. One logical approach is to always return an error in all cases of type mixing, but it is often practical to allow some case mixing, since it can hugely simplify an operation. Variation and lack of a clearly more intuitive behaviour leads some languages to have weird results when you mix types.

# <code>2 + "2"</code> uses the <code>+</code> operator on a number and a string. In some programming languages, this might result in the number <code>4</code> (addition), or <code>"22"</code> (string concatenation); however, the new language converts the string to an integer, adds them to produce <code>4</code> and converts back to a string. Alternately, it may instead be adding 2 to the ASCII value of the character <code>"2"</code> (50), resulting in the character <code>"4"</code> (52). This is (somewhat) consistent with the behavior for item 4.
# <code>"2" + []</code> adds a string to an array or list, this time. This first inexplicably converts the string to a number again, and then it literally adds the number to the list by appending it (this would make sense if it was <code>[] + 2</code>, but usually not the other way around). And then the result (the entire array) is converted to a string again.
# <code>(2/0)</code> divides <code>2</code> by <code>0</code> and quite reasonably results in <code>NaN</code> (not a number), though in most languages, as prescribed by the IEEE 854 standard for floating point numbers, dividing a nonzero number by zero would instead return an infinity value.
# <code>(2/0)+2</code> adds <code>2</code> to <code>NaN</code>. <code>2</code> is "added" to the string <code>"NaN"</code> (again, the number is converted to a string for apparently no reason), which produces <code>"NaP"</code>. If the language's convention is to add to the ASCII value of a character or string, then in this case it added 2 to the character <code>"N"</code> (78), resulting in <code>"P"</code> (80).
# <code>""+""</code>: In many languages, two consecutive double-quote characters denote an empty string, so this expression would concatenate two empty strings, resulting in an empty string. However, it appears that this language treats only the outermost quotes of the expression as the string boundary, so all of the characters between them become part of the literal string, producing '<code>"+"</code>'.
# <code>[1,2,3]+2</code> seems to test whether it's sound to append <code>2</code> to the list <code>[1,2,3]</code>, and concludes that it doesn't fit the pattern, returning the boolean value <code>false</code>. It could conceivably also be the result of an attempt to add <code>2</code> to the ''set'' <code>[1,2,3]</code>, which already contains that element (although <code>{1,2,3}</code> would be a more common notation for sets).
# <code>[1,2,3]+4</code> returns <code>true</code> for much the same reason.
# <code>2/(2-(3/2+1/2))</code> is a floating point joke. Floating point numbers are notoriously imprecise. With precise mathematics, <code>(3/2+1/2)</code> would be exactly 2, hence the entire thing would evaluate to <code>2/0</code> or <code>NaN</code> in Randall's new language. However, the result of <code>(3/2+1/2)</code> is "just slightly off," which makes the result "just slightly off" of <code>NaN</code> (which would be ridiculous in a real language). The ironic thing is that fractions with 2 in the denominator are ''not'' the kind of numbers that typically suffer from floating point impreciseness. Additionally, if there was indeed a rounding error, the actual calculation becomes something like <code>2/0.0000000000000013</code>, which should not return a <code>NaN</code> since it is not division by zero.
# <code>range(" ")</code> normally wouldn't make any sense. However, the new language appears to interpret it as ASCII, and in the ASCII table, character #32 is space, #33 is <code>!</code>, and #34 is <code>"</code>. So, instead of interpreting <code>" "</code> as a string, it seems to be interpreted as <code>34, 32, 34</code> (in ASCII), and then <code>range</code> appears to transform this into <code>34, 33, 32, 33, 34</code> (the "ranges" between the numbers), which, interpreted as ASCII, becomes <code>['"', '!', ' ', '!', '"']</code>.
# <code>+2</code> refers to the Chinese/Japanese (Kanji) number system, where the plus sign is instead the symbol <code>十</code>. In Chinese, this symbol represents the number ten, and if you translate the <code>2</code> into Chinese, you get <code>二</code>. Therefore, in full Chinese the code is <code>十二</code>, which is equivalent to the number <code>12</code>. Alternately, it could simply be attempting to add 2 to the line number 10 to get 12.
# <code>2+2</code> would normally be <code>4</code>. However, the interpreter takes this instruction to mean that the user wishes to increase the actual value of the number <code>2</code> (aka the "literal value") by <code>2</code> for the remainder of the program, making it <code>4</code> and then reports that the work is "Done". The result can be seen in the subsequent lines where all <code>2</code>s are replaced by <code>4</code>s. This could be a reference to languages like Fortran where [http://everything2.com/title/Changing+the+value+of+5+in+FORTRAN literals could be assigned new values].
# <code>range(1,5)</code> would normally return <code>[1, 2, 3, 4, 5]</code>. However, since the value of <code>2</code> has been changed to <code>4</code>, it returns <code>[1, 4, 3, 4, 5]</code>, and this even affects the line number (which is 14 instead of 12).
# <code>floor(10.5)</code> should return <code>10</code> (the "floor" of a decimal number is that number rounded down). However, it instead returns {{w|ASCII art}} of the number on a "floor."

The title text contains three further examples relating to color. <code>color.rgb("blue")</code> returns the hexadecimal code for pure blue (as would be used in HTML, for example), which is how a real programming language might work. The lookup for "yellowish blue" returns "NaN" (Not a Number) again, which makes sense at one level because there is no such color as "yellowish blue" (yellow and blue are opposites on the color wheel, making yellowish-blue an {{w|impossible colour}}, which can only be perceived with great difficulty through contrived figures). However a more typical result would have been a failure indicating that the color database does not include the name, in the same way that a typo such as "bluw" would. Similarly sorting the colors would normally produce some defined ordering, such as alphabetical, but in this language it generates the string "rainbow". It seems that Randall's new language understands color theory in an unusually deep way.

==Transcript==
My new language is great, but it has a few quirks regarding type:
<pre>
[1]> 2+"2"
=> "4"
[2]> "2"+[]
=> "[2]"
[3] (2/0)
=> NaN
[4]> (2/0)+2
=> NaP
[5]> ""+""
=> '"+"'
[6]> [1,2,3]+2
=> FALSE
[7]> [1,2,3]+4
=> TRUE
[8]> 2/(2-(3/2+1/2))
=> NaN.0000000000000013
[9]> range(" ")
=> ('"','!'," ","!",'"')
[10]> +2
=> 12
[11]> 2+2
=> DONE
[14]> RANGE(1,5)
=> (1,4,3,4,5)
[13]> FLOOR(10.5)
=> |
=> |
=> |
=> |
=> |___10.5___
</pre>
{{comic discussion}}

[[Category:Programming]]
[[Category:Language]]

1537: Types

2015-06-12T12:54:22Z

141.101.98.191: /* Explanation */

Talk:1480: Super Bowl

2015-01-30T16:41:28Z

141.101.98.191:

So should this be tagged as a my hobby comic? Not sure since it is only in the title text. [[User:Athang|Athang]] ([[User talk:Athang|talk]]) 08:25, 30 January 2015 (UTC)
: Looking through all the comics, I believe this is the first comic to have "My hobby:" in the title text. [[615|There is one that follows the same pattern]], but merely has "Hobby:" in the title text, which is not itself categorized as a "My Hobby" comic, but the explanation states it is a reference to that category. Personally, I don't see any reason NOT to put both of these (but at least this one, since it does actually have the words "My hobby:" in it's text, if only in the title text) into said category. But I'm not the only user of this site - anyone else want to weigh in? -- [[User:Brettpeirce|Brettpeirce]] ([[User talk:Brettpeirce|talk]]) 11:55, 30 January 2015 (UTC)
I'm wondering - has he duplicated a comic title before? -- [[User:Brettpeirce|Brettpeirce]] ([[User talk:Brettpeirce|talk]]) 10:26, 30 January 2015 (UTC)
: It looks like this is the second comic title to be duplicated - the other pair appears to be [[Exoplanets]] ([[786]] and [[1071]]) -- [[User:Brettpeirce|Brettpeirce]] ([[User talk:Brettpeirce|talk]]) 10:40, 30 January 2015 (UTC)
It's actually the Superb Owl in my world.[[Special:Contributions/108.162.216.35|108.162.216.35]] 10:48, 30 January 2015 (UTC)
: OMG! I ''LOVE'' the Superb Owl!!! THOSE EYES!!!!! -- [[User:Brettpeirce|Brettpeirce]] ([[User talk:Brettpeirce|talk]]) 10:53, 30 January 2015 (UTC)
The trouble with Arsenal is...--[[User:Bmmarti3|Bmmarti3]] ([[User talk:Bmmarti3|talk]]) 13:45, 30 January 2015 (UTC)
:...[http://www.youtube.com/watch?v=gWJIQm9qH-w they always try to walk it in]. [[Special:Contributions/141.101.98.191|141.101.98.191]] 16:41, 30 January 2015 (UTC)

Talk:1473: Location Sharing

2015-01-14T16:28:54Z

141.101.98.191:

It's a reference to the Uncertainty Principle, a property of quantum mechanics that states that position and momentum cannot be known at the same time.
[[Special:Contributions/199.27.133.98|199.27.133.98]] 05:20, 14 January 2015 (UTC)

I may be thinking too much into this, but couldn't she also not want the website to know her mass? Momentum is Mass*Velocity, and Velocity can be derived from change in position [[Special:Contributions/173.245.56.159|173.245.56.159]] 05:34, 14 January 2015 (UTC)
:That was my understanding, too. Moreover, I don't see any humor in applying the uncertainity principle to macroscopic objects. [[Special:Contributions/108.162.254.57|108.162.254.57]] 08:53, 14 January 2015 (UTC)

Angular momentum sensors - a.k.a. gyros, not accelerometers. {{unsigned ip|141.101.80.109}}

She does not want the website to calculate her mass and therefore her weight. It has nothing to do with the uncertainty principle {{unsigned|Saints22}}
:I disagree. Of course it is funny idea that she says nice try as if the website had interest in her weight. But since you cannot calculate mass from position and momentum your ideas makes no sense. You need the velocity and the momentum to calculate the mass. So even though they could have both position and momentum they would still not know her mass. --[[User:Kynde|Kynde]] ([[User talk:Kynde|talk]]) 10:33, 14 January 2015 (UTC)
::Unless, of course, the permission given by Megan to determine her location is persistent and lasts for at least two consecutive polls for location, which would enable the recipient to compute the velocity out of two locations and time between the polls. [[User:Nyq|Nyq]] ([[User talk:Nyq|talk]]) 13:12, 14 January 2015 (UTC)

I do not not think that Megan allows the website to access her location. The website wants her to, that's why the button is highlighted and blinking. In the beat panel, Megan presumably denies. The website then asks for momentum and wants Megan to deny the request (by highlighting "Deny"), so that, according to the uncertainty principle, they can still get her location (which is what they wanted all along). However, Megan sees through this trick and acknowledges its cleverness with a "Nice try". --[[Special:Contributions/108.162.254.134|108.162.254.134]] 10:27, 14 January 2015 (UTC)
:No I disagree. Of course the highlighted button is the one Megan pushes. And just because you do not know the momentum does not automatically give you the location. You just can't know both without a given uncertainty. --[[User:Kynde|Kynde]] ([[User talk:Kynde|talk]]) 10:33, 14 January 2015 (UTC)

What's with the persistent "females"? Would make sense in biology talk, but it's really weird when what you mean is "women"[[Special:Contributions/141.101.104.185|141.101.104.185]] 13:14, 14 January 2015 (UTC)
:: I'd suggest that it is just about avoidance: some might take 'women' as having negative derogative connotations in this context, whereas females is unarguably accurate. [[Special:Contributions/173.245.54.204|173.245.54.204]] 13:29, 14 January 2015 (UTC)
:::"Females" is shorter than "women and girls". [[Special:Contributions/108.162.221.201|108.162.221.201]] 14:54, 14 January 2015 (UTC)

There's some confusion over the sensors. GPS is used to determine the device's position on Earth, but not its orientation. An accelerometer may be used to determine a phone's orientation in terms of flat/portrait/landscape, but not in which direction in terms of north/south. The magnetometer can measure magnetic forces, but isn't enough to determine north (because of inclination). To measure magnetic north, you need to combine data from accelerometer and magnetometer, which gets a working, but quite unsteady compass. These sensors (GPS, accelerometer, magnetometer) are available on most current smart phones. Better devices also include a gyroscope, which measures angular momentum, but no absolute angle towards the horizon and/or north. A gyroscope may be used to improve the stability of the accelerometer/magnetometer compass (but requires a good algorithm which I'm still looking for). Knowing this, the title text is disputable, because devices without gyro aren't actually able to provide a steady compass, while those with gyro are (although there are apps which don't use the gyro even when available, so they won't get a fast, steady compass anyway). --[[User:SlashMe|SlashMe]] ([[User talk:SlashMe|talk]]) 15:24, 14 January 2015 (UTC)

It seems to me that the paragraph explaining mass and weight is too complicated and overly long, and the hypothesis that the app is trying to steal this information unrelated to the comic, or rather, wild speculative extrapolations of logic and meaning. Likewise, the sentences on how the accelerometer may be used to guess passwords seems to me to be unfounded in science. The uncertainty principle is the clear main theme of this comic. --[[User:Canned Soul|Canned Soul]] ([[User talk:Canned Soul|talk]]) 16:03, 14 January 2015 (UTC)

Added one word to make it "An example is a weather app which would need your location in order to '''automatically''' find the correct forecast." It's often trivial to manually get forecasts (or other services, like "nearest branch of a shop that has your desired item in stock") for a current location, just so as long as /you/ know where you are... (I don't turn on my GPS unless I'm actually wanting to use it for something, and don't like websites knowing these things just because they ask for them in the background. Go away, Google Location Services... and why does it grey-out the "Don't share information" hotspot when I've ticked the "Don't ask me again" and only lets me continually refuse ''manually''!? Which I do on principle!!) I keep a variety of common home/away locations on permalink in my favourite weather forecast app and know I can easily add another at a moment's notice when I ''want'' to. (And, the beauty is, I don't even need to be there at the time, just perhaps ''planning'' to go!)

Plus, to the "I don't see any humor in applying the uncertainity principle to macroscopic objects." person, above, please pass by your local XKCD offices at the first opportunity in order to hand back your XKCD Membership Card. You're obviously not one of us! ;) [[Special:Contributions/141.101.98.191|141.101.98.191]] 16:28, 14 January 2015 (UTC)

1473: Location Sharing

2015-01-14T16:17:15Z

141.101.98.191: /* Explanation */ One word added for clarity.

{{comic
| number = 1473
| date = January 14, 2015
| title = Location Sharing
| image = location_sharing.png
| titletext = Our phones must have great angular momentum sensors because the compasses really suck.
}}

==Explanation==
{{incomplete|First draft.}}

In this comic, [[Megan]] is visiting a website on her mobile phone. After loading it, the website {{w|Location-based service|asks for her location}}, which Megan permits the phone to give. The choice between allowing or denying a website or app access to certain information is common among smartphones. The term "location sharing" specifically refers to when a smartphone user shares their location with such an entity. An example is a weather app which would need your location in order to automatically find the correct forecast.

Megan is then asked her {{w|momentum}}, which she denies. The joke is based off of the Heisenberg {{w|uncertainty principle}}, which, in quantum mechanics, states that one cannot accurately know both the location and momentum of any particle simultaneously. However, since Megan is not a microscopic particle, it doesn't make any sense (it's simply funny) to say the the app is trying to violate Heisenberg's principle.

The ramifications of the uncertainty principle being violated in this context are unknown, but the comic might be alluding to security problems that appear if an untrusted application is given access to momentum data generated by the gyroscope. Access to gyroscope data can be used for reading passwords entered into the on-screen keyboard or even guessing keyboard strokes on a keyboard lying on the same table as the phone.

It could also be an attempt to get [[Megan]] to unwillingly reveal her weight (mass to be more exact), as the her mass can be inferred by dividing the momentum by her velocity (the velocity can be obtained by observing the change of her location information in time). In order to be feasible, however, the location must be polled at least twice, not once, as at least two location points are necessary to compute the velocity. Also, although commonly used interchangeably, the mass and the weight are not the same things. The mass is a measure of mechanical inertia of the body, while the weight is the force on the object due to gravity. As such, the weight of the same body is different on the surfaces of different celestial bodies (planets, etc). The weight can be computed from the mass by multiplying the latter by the {{w|Gravitational acceleration|gravitational acceleration}} of the given planet (obviously, Earth in this case). The tendency to keep the body weight in secret is a common stereotype about females, as it is believed that females tend to obsess about controlling (and not revealing) their weight in order to comply with the perceived expectations of the modern Western male society which tends to find slim females more attractive.

The title text refers to the inclusion of {{w|gyroscope}}s in modern cell phones that measure angular momentum, mostly to detect when the phone is tilted, but also used in a few mobile games. Randall suggests the poor accuracy of the compasses in mobile phones (measuring the angular position) is due to the gyroscopes being too good. (If both the gyroscope and the compasses were completely accurate, it would violate the uncertainty principle). Modern phones also include varied technologies (such as GPS) to pinpoint the user's location, with varying degrees of accuracy.

There is no way to measure absolute momentum directly in a mobile phone (well, anywhere else either). This is done normally by differentiating the position in time (from GPS signal) or by integrating the accelerometer signal. In the first case you obtain the average speed, the second technique is subject to numerical error adding up in time.

The uncertainty principle has previously been referenced in [[824: Guest Week: Bill Amend (FoxTrot)]]. It has also been discussed in relation to the two comics [[1404: Quantum Vacuum Virtual Plasma]] and [[1416: Pixels]].

==Transcript==
:[Megan is holding her phone. Above her is the text she can see on the screen:]
:This website wants to know your location.
:[Two buttons are below this text. The first is white with a black frame and black text. The second (the chosen button) also has a black frame, but inside the frame is a black rectangle with white text. Around the chosen button are small lines indication rays.]
:Deny
:'''Allow'''

:[Megan is holding her phone.]

:[Megan is holding her phone. Above her is again the text she can see on the screen. She makes a comment this time.]
:This website wants to know your momentum.
:[Two buttons are below this text. The first (the chosen button) has a black frame, but inside the frame is a black rectangle with white text. The second is white with a black frame and black text. Around the chosen button are small lines indication rays.]
:'''Deny'''
:Allow

:Megan: Nice try.

{{comic discussion}}
[[Category:Comics featuring Megan]]

Talk:1472: Geography

2015-01-12T13:55:54Z

141.101.98.191:

Anybody notice that he drew an isthmus but didn't label it? [[Special:Contributions/108.162.221.94|108.162.221.94]] 05:49, 12 January 2015 (UTC)

Does Randall play Dwarf Fortress? Because the perfect map to build your fort on looks about like this. Volcano near the sea is especially neat luxury. --[[Special:Contributions/141.101.80.121|141.101.80.121]] 06:57, 12 January 2015 (UTC)

:[[1223: Dwarf Fortress]] suggests he does. --[[User:Pudder|Pudder]] ([[User talk:Pudder|talk]]) 09:00, 12 January 2015 (UTC)

Would be nice if there could be an example of the sort of map that Randall is referring to from a textbook for people who've never seen them or don't remember. {{unsigned ip|199.27.128.91}}
Yeah, shame that there isn't one in the comic itself... [[Special:Contributions/108.162.216.109|108.162.216.109]] 12:58, 12 January 2015 (UTC)

I'd be interested to hear where in the world people claim matches this best. Boston...? I ain't buying that one. {{unsigned ip|108.162.225.44}}

Examples like Randall was talking about that I found on Google images.
[http://www.aparisgarcia.net/advwebdesign/LandandWaterFeaturesmap.jpg 1]
[https://ts-cdn-teachstarterptyl.netdna-ssl.com/wp-content/uploads/2014/04/TeachingResources_GeographicFeatures_Poster_US.jpg 2]
These appear to be two pages of the same picture: [http://secageography.weebly.com/uploads/2/4/8/8/24881589/2206129_orig.jpg 3] [http://secageography.weebly.com/uploads/2/4/8/8/24881589/9094980_orig.jpg 4]
I'm not sure if they're good enough quality to add to the main article, but if someone thinks they are, feel free. For someone who's never seen them before, they're fairly common in elementary school social studies or geography textbooks; I remember seeing them multiple times in mine. [[User:Tomari7|Tomari7]] ([[User talk:Tomari7|talk]]) 11:10, 12 January 2015 (UTC)

Also, no Valley or Fjord. Damn insensitve tropical geography.[[Special:Contributions/108.162.254.98|108.162.254.98]] 11:21, 12 January 2015 (UTC)

The Region around Vancouver has a lot of the items in the picture. (Sandy) deserts and Mesas are the only missing. {{unsigned ip|141.101.64.137}}

Anyone else noticing the distinct lack of any buildings? I'd call that a reason not to live there...
:...well, there's My House.;) [[Special:Contributions/141.101.98.191|141.101.98.191]] 13:55, 12 January 2015 (UTC)

1467: Email

2014-12-31T13:28:34Z

141.101.98.191: /* Explanation */

{{comic
| number = 1467
| date = December 31, 2014
| title = Email
| image = email.png
| titletext = My New Year's resolution for 2014-54-12/30/14 Dec:12:1420001642 is to learn these stupid time formatting strings.
}}

==Explanation==
[[Beret Guy]] doesn't seem to know what an email is, even though the term has existed since 1993, been in use by the general public since 1998 when free email providers appeared and he even apparently personally maintains a web-page upon which he placed his(/an) email address. [[Megan]] is visibly appalled and wonders how else he expects electronic messages to be sent. She says that you have to check your e-mail as it is not like {{w|voicemail}} - thus saying that it is OK not to check voicemail.

Beret guy offers two alternatives: fax and {{w|Snapchat}}. When Megan tries to point out that Snapchat is mostly used to send naked pictures, Beret guy takes her to mean that fax is mostly used to send naked pictures. He terms this use of faxes faxting, a made-up word by analogy with {{w|sexting}}.

The title text shows what is possibly [[Randall|Randall's]] new years resolution: to learn how to use time formatting functions. When programming, it is often useful to obtain the current time by means of a time function. However, these time functions often provide more detail than what the programmer needs, such as time zone and milliseconds. Time formatting functions allow the output of the time function to be converted into what the programmer needs.

Randall appears to have used a time function to get the current date, probably with the formatting string "%Y-%M-%D %h:%m:%s", which looks like it should give year-month-day hour:minute:second, but when parsed by standard {{w|Unix}} routines gets interpreted as follows:

%Y is 4-digit year
%M is minute
%D is the same as %m/%d/%y, i.e. month/day/(2-digit)year
%h is the abbreviated month name
%m is 2-digit month
%s is the Unix timestamp

The {{w|Unix time|Unix timestamp}} 1420001642 that comes from the %s can be seen at the end of the date in the title text. This corresponds to the date 2014-12-31 at 04:54:02 UTC. This will hence give the full time string 2014-54-12/31/14 Dec:12:1420001642 from the above string.

The correct formatting string for year-month-day hour:minute:second would be %Y-%m-%d %H:%M:%S which would have given the wanted output: 2014-12-31 04:54:02.

The trouble with using the correct date format has been mentioned in [[1179: ISO 8601]] and the correct date format was used in [[1340: Unique Date]].

==Transcript==
:[Megan approaches Beret Guy.]
:Megan: Any New Year's resolutions?
:Beret Guy: Gonna figure out what email is.
:Megan: ''...Email?''

:[Megan points to her phone.]
:Beret Guy: People always say they're sending them. They sound really into it, so I always nod, but I have no idea what it is.
:Megan: You have an address on your website!

:[Megan and Beret Guy walking.]
:Beret Guy: Oh, ''that's'' what that thing is.
:Megan: Email is important! You can't just ''never'' check it. It's not like voicemail.

:Beret Guy: Can't they just send messages ''normally?''
:Megan: How?
:Beret Guy: Fax! Or Snapchat.
:Megan: ...The naked pic thing?
:Beret Guy: Fax machines aren't ''just'' for faxting!
{{comic discussion}}
[[Category:Comics featuring Beret Guy]]
[[Category:Comics featuring Megan]]

Talk:1467: Email

2014-12-31T13:23:24Z

141.101.98.191:

The strftime format used is probably %Y-%M-%D %h:%m:%s, which visibly looks as if it will yield a date and time, yet doesn't. A more correct format would have been %Y-%m-%d %H:%M:%S. {{unsigned ip|‎197.234.242.236}}

There's a strange thing with the date string : why 30 ? The timestamp shows 31 as a day in month and 5:54 which doesn't match 30... 54 looks like the week in year but matches with the minutes. [[User:Goufalite|Goufalite]] ([[User talk:Goufalite|talk]]) 09:57, 31 December 2014 (UTC)

What on earth does 'Created for a live studio audience mean'?! [[Special:Contributions/141.101.106.143|141.101.106.143]] 10:03, 31 December 2014 (UTC)

"Unix" is misleading. Sure, unix "date" command is using this kind of formating, but it's also in C standard (specifically, C89 and C99) and available in most other programming languages standard libraries (including perl, php, python, ruby), often as ONLY way to format date without fetching every component separately. -- [[User:Hkmaly|Hkmaly]] ([[User talk:Hkmaly|talk]]) 13:15, 31 December 2014 (UTC)

I'm fairly confident that I used the term "email" before 1993, because of what I was doing before that date. But I also couldn't give any definitive sources. And I mean the name, not just the general Port 25 thing or its predecessors. But meh, no real proof unless I get lucky digging around in 5.25" floppies for old backups that I doubt I could read anyway... [[Special:Contributions/141.101.98.191|141.101.98.191]] 13:23, 31 December 2014 (UTC)

Talk:1466: Phone Checking

2014-12-30T15:05:41Z

141.101.98.191:

''No comments yet.''
I'll keep refreshing. [[Special:Contributions/108.162.217.125|108.162.217.125]] 06:40, 29 December 2014 (UTC)BK201

What's a 'webite'? [[Special:Contributions/199.27.128.178|199.27.128.178]] 08:51, 29 December 2014 (UTC)

:I think it's a term related to the [[148: Mispronouncing|"wobsite"]]. --[[User:Koveras|Koveras]] ([[User talk:Koveras|talk]]) 09:41, 29 December 2014 (UTC)

He first refreshed the web(s)ite and thén woke up? [[User:NGLN|NGLN]] ([[User talk:NGLN|talk]]) 14:38, 29 December 2014 (UTC)
: I believe it is possible to check one's phone while sleeping (i.e. partly asleep) and not remember having done so in the morning. Research is needed into this matter. [[User:Mrob27|Mrob27]] ([[User talk:Mrob27|talk]]) 14:54, 29 December 2014 (UTC)

The title text implies that checking the phone is an even more fundamental resting state for her than sleeping. As an analogy, you may subconsciously play with a sharp object while watching TV. You don't notice it until it pricks you. Same way, she was checking her phone while sleeping. Noticing that she'd won made her wake up. -quantumfrost {{unsigned ip|173.245.62.105}}

My interpretation is that this refreshing is a continuation of the contest. Maybe they either are adding this data to their original data, or this is a second contest, or this refreshing is the actual contest, because all the contest entry and judging was either a ruse, or the data was lost somehow. --[[Special:Contributions/199.27.128.192|199.27.128.192]] 20:54, 29 December 2014 (UTC)

"The title text implies that Megan checks her phone so compulsively she even does it in her sleep. This probably contributed to her victory." - There's no indication that the titletext relates to Megan, and not just any other eventual winner... But it could be, of course. [[Special:Contributions/141.101.98.191|141.101.98.191]] 15:05, 30 December 2014 (UTC)

Talk:1464: Santa

2014-12-28T20:42:28Z

141.101.98.191:

Merry Christmas! --[[User:RenniePet|RenniePet]] ([[User talk:RenniePet|talk]]) 06:29, 24 December 2014 (UTC)

I think I have done the transcript... [[User:17jiangz1|17jiangz1]] ([[User talk:17jiangz1|talk]]) 06:38, 24 December 2014 (UTC)

And I did the explanation and put everything in there, I think. Looks like we're already pretty much done! [[Special:Contributions/173.245.56.174|173.245.56.174]] 06:44, 24 December 2014 (UTC)

It should maybe be mentioned that this comic is a turn of the screw on the many "The physics of Santa" joke articles - The usual chain e-mail or satire web page calculations that take it seriously the logistical calculations for Santa and end up concluding that he should beat the speed of light to deliver the presents. Randall doesn't settle on calculating the logistics for reindeer performance or route planning, he goes a step further and makes the calculations for the refuse. [[Special:Contributions/173.245.49.106|173.245.49.106]] 08:31, 24 December 2014 (UTC)

Well maybe all those calories are what allows him to move at the insane relativistic speeds needed to visit every house on Christmas eve. [[Special:Contributions/108.162.216.56|108.162.216.56]] 08:47, 24 December 2014 (UTC)
: Exactly. And even if it wasn't, there'd still be a Mr Fusion for the poop. [[Special:Contributions/108.162.250.214|108.162.250.214]] 22:18, 24 December 2014 (UTC)
:There's no need to move at relativistic or trans-light speeds when you can appear in multiple places simultaneously [https://comicdomwrecks.wordpress.com/2010/10/01/countdown-to-fables-100-jiminy-christmas/]. - Equinox [[Special:Contributions/199.27.128.117|199.27.128.117]] 17:41, 24 December 2014 (UTC)

We have video proof of how Santa handles this! http://youtu.be/b9TTz3R5SmI --[[User:Elipongo|Elipongo]] ([[User talk:Elipongo|talk]]) 09:03, 24 December 2014 (UTC)

No Christmas cat.? [[User:Halfhat|Halfhat]] ([[User talk:Halfhat|talk]]) 12:12, 24 December 2014 (UTC)

Santa's metabolic system is perfectly efficient at converting cookies to CO2 hang H2O which is exhaled. He needs to be efficient at converting cookie energy if he plans on being so active. He is also the main source of global warming. [[Special:Contributions/173.245.56.185|173.245.56.185]] 13:11, 24 December 2014 (UTC)

As a third option, what if Santa doesn't eat the cookies at all, but just redistributes them to other hungry children? --[[Special:Contributions/108.162.217.131|108.162.217.131]] 18:41, 24 December 2014 (UTC)

Perhaps understandably, I first read the line in the explanation as " ... butt off the side of his sleigh." [[User:Miamiclay|Miamiclay]] ([[User talk:Miamiclay|talk]]) 22:27, 24 December 2014 (UTC)

As a native English speaker, I'd like to say that "few" is relative, and defies any hard limits. A "few" transistors, for me, might mean dozens (as opposed to hundreds or more). A "few"lightyears might be 10 or so. The use of the word "few" can't be analyzed with such hard limits as 2 to 5. [[Special:Contributions/108.162.221.169|108.162.221.169]] 17:47, 25 December 2014 (UTC)

There are only a few countries where kids leave cookies for Santa (I'm guessing North America and some European countries). That would mean fewer than 100 million kids. [[Special:Contributions/103.22.200.195|103.22.200.195]] 05:36, 26 December 2014 (UTC)

: 32% of the world population are christians, and even some non-christians celebrate Christmas. [[User:17jiangz1|17jiangz1]] ([[User talk:17jiangz1|talk]]) 09:56, 26 December 2014 (UTC)

:: Yes, but leaving cookies for Santa is not integral part of christian Christmas celebration, not speaking about non-christian. There are more children who believe Santa is bringing them gifts than children who are leaving cookies for Santa. -- [[User:Hkmaly|Hkmaly]] ([[User talk:Hkmaly|talk]]) 13:53, 27 December 2014 (UTC)

::: Some children may be leaving cookies "for Santa", but suspect that their parents (or older siblings) are actually consuming them. It may be possible that Santa is not consuming as many cookies as this comic estimates.

:::: Maybe, but he's gotta be eating most of them. There's no way parents can eat all those cookies in one night! [[Special:Contributions/108.162.221.169|108.162.221.169]] 07:24, 28 December 2014 (UTC)

::: Cookies aren't (traditionally) left in the UK. Even with the usual translation of "cookie" as "biscuit". A glass of sherry and a mince pie is our variant (at least locally to me), and of course a carrot for Rudolph. Or one or other of whichever of the on-duty reindeer is next due a nibble, which would somewhat mitigate the problem of "carrot throughput" similar to the cookie one, although ultimately mid-air ejection is probably the answer in their case anyway. [[Special:Contributions/141.101.98.191|141.101.98.191]] 20:42, 28 December 2014 (UTC)

BHG

2014-10-12T11:07:55Z

141.101.98.191: Redirected page to Black Hat

#REDIRECT [[Black Hat]]

Talk:1416: Pixels

2014-09-04T15:26:28Z

141.101.98.191: Added comment about having the same issue.

Firefox users with HTTPS Everywhere may have trouble seeing the comic, and Chrome users may experience lag (for lack of a better word) when zooming in. [[Special:Contributions/141.101.99.168|141.101.99.168]] 06:11, 3 September 2014 (UTC)

The combination of "turtle" and "pixel" reminded me of how to code graphics in the older days with for instance turbo pascal (http://en.wikipedia.org/wiki/Turtle_graphics) - Stian

Would it be possible to have a "gallery" of all the zoom-in images? [[Special:Contributions/199.27.128.209|199.27.128.209]] 06:29, 3 September 2014 (UTC)

Since the Zoom-in images have at lest one story line in them (I read one about a book launch, the book was launched to space in a rocket), I think a gallery or some such is needed for them. [[Special:Contributions/108.162.250.218|108.162.250.218]] 06:50, 3 September 2014 (UTC)

I got to a white panel and there was nothing. Everything was white and zooming in or out didn't change it. Not sure if it was a bug or intended. -- [[User:Irino|Irino]] ([[User talk:Irino|talk]]) 07:15, 3 September 2014 (UTC)
* That happens to me when I click on the image in Chrome. Not sure why. [[User:Castriff|Jimmy C]] ([[User talk:Castriff|talk]]) 21:35, 3 September 2014 (UTC)

Yet another comic that doesn't work well on mobile. I'll probably compile a list of comics that are broken in some way for mobile... Er. Soon-ish. -RTR [[Special:Contributions/108.162.246.232|108.162.246.232]] 07:45, 3 September 2014 (UTC)

I have acquired a list of images with what they zoom into, and am working on turning that into something presentable. There's a lot of images though, so it may take a day. As for the white panel, yes, there does seem to be one broken link (out of nearly 500). I'm not sure how I would go about reporting it to get it fixed. [[User:Tahg|Tahg]] ([[User talk:Tahg|talk]]) 07:57, 3 September 2014 (UTC)

There are 79 different images. I have them isolated and am uploading them now. [[User:Omixorp|Omixorp]] ([[User talk:Omixorp|talk]]) 08:16, 3 September 2014 (UTC)
:Cool - the images are here - if you click on the broken links they can be seen. But why are they not visible? They take up a lot of space, so I have moved them to a separate gallery page as has been done with [[1350: Lorenz]]. [[User:Kynde|Kynde]] ([[User talk:Kynde|talk]]) 11:44, 3 September 2014 (UTC)
::I think there's a problem with all thumbnails across this site - even old thumbnails don't seem to be working right now. [[User:Omixorp|Omixorp]] ([[User talk:Omixorp|talk]]) 10:31, 3 September 2014 (UTC)
:::They work on Lorenz that I have linked to in my comment above. [[User:Kynde|Kynde]] ([[User talk:Kynde|talk]]) 11:44, 3 September 2014 (UTC)

Doesn't work at all (blank) on my Firefox and IE11. I just installed Opera and it works but it's VERY laggy. Also, I have to scroll UP to zoom in, not down. --[[Special:Contributions/141.101.97.206|141.101.97.206]] 08:25, 3 September 2014 (UTC)
:Neither on Firefox 31.0. Zooming until the first level of pictures, I see them appearing. But when they are larger than ~20 pixels they start to disappear. They only reappear intermittently when I pan or zoom. When I zoom in further, only images on the left side appear intermittently. This shows the grid is built from left to right, then top to bottom, and it just stops randomly. --[[User:Zom-B|Zom-B]] ([[User talk:Zom-B|talk]]) 20:32, 3 September 2014 (UTC)
:I'm having different problems with both Firefox 31.0 and 32.0 on Windows. When zooming in, all pixels (including white parts of the image) resolve to images with black background, so I never see the "white" ones (except for the initial "turtles" one). Anyone having the same problem? IE11 works for me. [[Special:Contributions/141.101.99.186|141.101.99.186]] 21:52, 3 September 2014 (UTC)
::I also have this issue, using Firefox 31.0 on Windows 7. It's also very slow/laggy doing the fade transitions between pixels and the images.

This date of this comic (Sept 3rd 2014) coincided with the date of Randall's book, What-If. This book is shown or referenced in a number of the frames.--[[User:Pudder|Pudder]] ([[User talk:Pudder|talk]]) 09:57, 3 September 2014 (UTC)
:But the site says the book was out September 2nd... [[Special:Contributions/108.162.237.161|108.162.237.161]] 11:21, 3 September 2014 (UTC)
::You're right, 108.162.237.161. I changed it and provided proof. As far as I could find, though, it's only launched in the US as of today. [[User:NealCruco|NealCruco]] ([[User talk:NealCruco|talk]]) 19:21, 3 September 2014 (UTC)

Also just isolated the images. I described the procedure on my blog: http://azttm.wordpress.com/2014/09/03/xkcd-com-1416-pixels/ [[User:Azt|Azt]] ([[User talk:Azt|Azt]]) 09:58, 3 September 2014 (UTC)

I zoom in when I scroll up. I also like turtles. [[Special:Contributions/103.22.201.120|103.22.201.120]] 09:15, 3 September 2014 (UTC)

I think this comic might be a reference to D. Hofstadter's celebrated book ''Gödel, Escher, Bach'', what with the 'holism', 'reductionism' and 'Mu' coming out at some point (there is the very same construction in one of the dialogs from that book). Plus, generally speaking, ''GEB'' is all about "strange loops" and infinite recursions. --[[Special:Contributions/108.162.254.30|108.162.254.30]] 09:50, 3 September 2014 (UTC)

I have uploaded a graph showing the layout of the entire storyline, with thumbnails of the individual images, at [[Media:1416_Pixels_layout.png]]. --[[User:Mnw21cam|Mnw21cam]] ([[User talk:Mnw21cam|talk]]) 12:20, 3 September 2014 (UTC)

Has any attempt been made to find "extra" panels that may occur as a part of a logical series? For example, there is "chess-b" and "chess-w", are there "chess-a", "chess-c", "chess-d", etc? [[User:Jarod997|Jarod997]] ([[User talk:Jarod997|talk]]) 13:56, 3 September 2014 (UTC)
:It never occurred to you that those letters stand for Black/White? --[[User:Zom-B|Zom-B]] ([[User talk:Zom-B|talk]]) 20:25, 3 September 2014 (UTC)
::Huh, wha? No, that's got to be way too simple. There MUST be more images! :P Actually I was hoping/wondering if there was a sequence of 20-ish chess panels which depicted a game, with a Randall type ending to it. *sigh* Way to burst my bubble. lol [[User:Jarod997|Jarod997]] ([[User talk:Jarod997|talk]]) 12:37, 4 September 2014 (UTC)

Any Kerbal Space Program players on here who can shed any light on the origins of 'Need Moar Struts'? Is it a well known meme amongst the player base as I have guessed?--[[User:Pudder|Pudder]] ([[User talk:Pudder|talk]]) 14:27, 3 September 2014 (UTC)

In an infinite series of turtles, at least 4 of them have to be youthful, genetically modified, and skilled in martial arts. Has anyone found them? [[User:DivePeak|DivePeak]] ([[User talk:DivePeak|talk]]) 21:30, 3 September 2014 (UTC)

I am on Chrome, and I cannot see any of the images in the Explain XKCD gallery even though the actual strip works fine. Anyone know what's wrong? [[User:Castriff|Jimmy C]] ([[User talk:Castriff|talk]]) 21:35, 3 September 2014 (UTC)

I don't know why the article says that the comic doesn't work in Safari on Mac OS X. It's working just fine here on Safari 7.0.6. I think if someone is going to make such claims, they should be careful to note which version of the software they're working with so others can compare appropriately. [[User:Yaztromo|Yaztromo]] ([[User talk:Yaztromo|talk]]) 23:33, 3 September 2014 (UTC)

;Adjacency list for the graph

I've created a quick hack to show what each image can contain [http://uber5001.github.io/turtles/ here]. Might be helpful in finishing off this page. [[User:Uber5001|Uber5001]] ([[User talk:Uber5001|talk]]) 22:48, 3 September 2014 (UTC)

;Mandelbrot?
Is the way the images are repeated being based on some math pattern, like the Mandelbrot set? [[User:Osias|Osias]] ([[User talk:Osias|talk]]) 02:38, 4 September 2014 (UTC)

; Quarks and strings?
Once when zooming I have found something that looked roughly like quark model of nucleon (below MU), then a loop - perhaps a string from the string theory --[[User:JakubNarebski|JakubNarebski]] ([[User talk:JakubNarebski|talk]]) 10:53, 4 September 2014 (UTC)

;Interactive graph
Hello, I've uploaded an interactive version of the graph [http://velt.info/xkcdpixels here] [[User:Raphv|Raphv]] ([[User talk:Raphv|talk]]) 15:16, 4 September 2014 (UTC)