explain xkcd - User contributions [en]

1194: Stratigraphic Record

2023-05-30T23:41:39Z

Final Exam: added dark text category

{{comic
| number = 1194
| date = April 3, 2013
| title = Stratigraphic Record
| image = stratigraphic record.png
| titletext = All we have are these stupid tantalizing zircons and the scars on the face of the Moon.
}}

==Explanation==
We have no rock formations on Earth older than about 3.5 billion years, as the comic points out, because everything solid from before that time has been {{w|Subduction|subducted}} down into the {{w|Mantle (geology)|Earth's mantle}}, by {{w|Plate tectonics|tectonic movement}}. The title text hints at the cooler {{w|Moon}} which stopped re-melting its surface much sooner, so we theoretically could learn something about Earth's history from examining our Moon's surface and makeup. {{w|Zircon|Zircons}} are a type of mineral found in the {{w|Crust (geology)|Earth's crust}}, some of which have been estimated to be as old as 4.4 billion years, older than any other mineral.

Anyways, here the Earth is anthropomorphized and actively teases the narrator; first it asks the narrator to draw in closer, as if it's about to tell us a secret, but then it whispers "I'll never tell".

==Transcript==
:[Image of the Earth in color as seen from far off in space with pitch black around the Earth. Two blocks of text are above and below the Earth in white rectangles:]
:Nearly 4.5 billion years ago, Earth had liquid water.
:But all the crust older than 3.5 billion years has been recycled into the mantle by subduction.

:[Same image of Earth, but now with only the middle of the panel black. Above and below is white sections (without a frame) with text:]
:A billion years of the stratigraphic record, the memory of the hills, is forever lost to us.
:What was it '''''like''''' here, four billion years ago?

:[A slimmer panel as the first, with two smaller white rectangles with text above and below:]
:Earth,
:What '''''secrets''''' do you have?

:[Similar panel, but now without the white rectangles. Instead a line comes up from the Earth as it speaks with white text, and in small letters, unlike normal xkcd text:]
:Earth: come closer

:[Zoom in on the Earth so it now fills almost the entire panel from left to right.]

:[Further zoom in on the Earth so now only part of the Earth can be seen in the panel. There is still black above, but not on the other three sides of the panel, which is filled with the Earth. It shows the northern part of the Earth with Alaska, Canada and some of mainland USA with one of the great lakes visible at the top right. The sea ice at the North Pole is also visible as are a small part of Russia near Alaska. Again the Earth speaks as in the first panel:]
:Earth: ''i'll never tell.''

{{comic discussion}}

[[Category:Comics with inverted brightness]]
[[Category:Comics with color]]
[[Category:Comics with lowercase text]]
[[Category:Geology]]

Transcript

2023-05-30T22:55:49Z

Final Exam:

Most [[xkcd]] comics have a transcript posted on xkcd. This info covers details like the comics title, the date and link to the image and the [[title text]]. The [https://www.xkcd.com/about/ xkcd about page] says:

{{Quote|Is there an interface for automated systems to access comics and metadata?
:''Yes. You can get comics through the JSON interface, at URLs like https://xkcd.com/info.0.json (current comic) and https://xkcd.com/614/info.0.json (comic #614).|[[Randall Munroe]]|[https://www.xkcd.com/about/ about xkcd]}}

The official transcript is different from the ones on Explain xkcd, which are more detailed and descriptive. Randall occasionally cites Explain xkcd for the transcript, like for the comic [[1461: Payloads]]. You can find more information in the [[1461: Payloads#Trivia|comic's trivia section]].

==End of transcripts==
{{incomplete|Does anybody know why the code block at the end of the page doesn't work? I've tried everything and it still looks like plain text}}
Using the mentioned method, the last available transcript on xkcd for [[1608: Hoverboard]] can be found at https://xkcd.com/1608/info.0.json. However, an error occurred during the combination of transcripts with other details. The subsequent two comics after Hoverboard do not have transcripts, only the accompanying details such as title, date, and title text. Then, the transcripts resumed, but for the comic released two numbers prior. Therefore, the transcript for [[1609: Food Combinations]], which should have been on https://xkcd.com/1609/info.0.json, was instead "released" on https://xkcd.com/1611/info.0.json, where the transcript for [[1611: Baking Soda and Vinegar]] should have been. The pattern continued, and the last comic with a transcript is [[1674: Adult]], with the transcript for that comic found three comics later under [[1677: Contrails]] on https://xkcd.com/1677/info.0.json. After [[1674: Adult]], no more transcripts have been provided.

This python script (public domain) can be used to quickly verify if and where new transcripts have been added:

<pre>#!/usr/bin/env python3
import requests
import sys

last_known_transcript = 1677
latest = requests.get(url='https://xkcd.com/info.0.json').json()['num']

new_transcripts = False
for i in range(latest, last_known_transcript, -1):
sys.stderr.write('.')
sys.stderr.flush()
if requests.get(url='https://xkcd.com/'+str(i)+'/info.0.json').json()['transcript'] != '':
print("\n", i, "has a transcript")
new_transcripts = True
print()

if not new_transcripts:
print("no new transcripts have been added")</pre>

[[Category:Design of xkcd]]
{{xkcdmeta}}

Talk:2385: Final Exam

2023-04-24T00:48:50Z

Final Exam: Final Exam reverts the spam on Final Exam.

Perhaps add a note about how multiple people trying to achieve the same goal would be impossible, so therefore it would be a test of game theory to see how the final grades end up. You'd want to be the last one to make all the changes. [[Special:Contributions/162.158.107.197|162.158.107.197]] 23:51, 13 November 2020 (UTC)
:It's a contest to hack the grades ''and'' to lock out all of the other students from making further changes. [[User:BunsenH|BunsenH]] ([[User talk:BunsenH|talk]]) 00:49, 14 November 2020 (UTC)
Title text seems to be a reference to https://en.wikipedia.org/wiki/Guess_2/3_of_the_average.
[[User:Anonymous3|Anonymous3]] ([[User talk:Anonymous3|talk]]) 01:10, 14 November 2020 (UTC)

The current "change every fifth answer to the bubble below it" explanation appears to make the implausible assumption that the exam is multiple-choice. [[User:BunsenH|BunsenH]] ([[User talk:BunsenH|talk]]) 03:19, 14 November 2020 (UTC)

Clearly the optimal solution for both courses is to change the grade to be ''out of 0'', thus a score of 0 being a perfect score and also meet the requirements for Game Theory. [[Special:Contributions/162.158.165.54|162.158.165.54]] 03:28, 14 November 2020 (UTC)

:great idea! i was considering adding fake students to be statistical extremes but your solution allows all students to ace both courses. [[User:Ocæon|ocæon]] ([[User talk:Ocæon|talk]]) 14:46, 14 November 2020 (UTC)

:That's a great way to get a division by zero error somewhere. [[Special:Contributions/162.158.222.155|162.158.222.155]] 21:59, 28 January 2022 (UTC)

OMG I want so much to take this class, what an excellent final exam![[Special:Contributions/172.68.65.208|172.68.65.208]] 05:09, 14 November 2020 (UTC)

I think the explanation above is largely correct, but I assumed this was a Zoom reference. Since during lockdown the many students she is addressing should be experiencing this through a remote meeting, for which Zoom is often chosen (I'd love an explanation as to why THAT is). Zoom has notorious security flaws which any cybersecurity student should be failed for accepting.
--[[Special:Contributions/162.158.159.96|162.158.159.96]] 05:11, 14 November 2020 (UTC)
:What if they run it in sandboxed virtual machine? -- [[User:Hkmaly|Hkmaly]] ([[User talk:Hkmaly|talk]]) 20:45, 14 November 2020 (UTC)

No mention of Bobby Tables? [[User:Gvanrossum|Gvanrossum]] ([[User talk:Gvanrossum|talk]]) 06:29, 14 November 2020 (UTC)
:That was a mom intentionally hacking multiple systems. Not just school, but also population census systems. This is limited to a single test. [[Special:Contributions/141.101.98.38|141.101.98.38]] 21:08, 14 November 2020 (UTC)

the zero length exam reminds me of 'zero day' exploits, the students have zero time to respond to the exam requirements before the conclusion of the exam. [[User:Ocæon|ocæon]] ([[User talk:Ocæon|talk]]) 14:39, 14 November 2020 (UTC)

I feel like Randall missed a golden opportunity for Danish (instead of generic Ponytail) to prof these classes — this seems right up her alley. [[User:TPS|TPS]] ([[User talk:TPS|talk]]) 16:17, 14 November 2020 (UTC)

1) Hack my Cybersecurity grade, 2) Hack the professor's computer to remove the requiring link to the grade in the other course. -Diana

There is exactly one Nash Equilibria if you set the utility function to be the sum of the cyber security grade and the game theory grade. And it would be to give yourself a 100% in cyber security - Philip Geißler

This cartoon reminded me of a programming class I took as a Freshman at MIT (Spring 1974) where the first lecture described the way the programming projects were submitted and automatically graded. "Some of you may be considering finding a way to hack the grading program to just give you a good grade. This is an acceptable way to pass this course, since it is our analysis that subverting the grading program in this way demonstrates mastery of the subject matter." OK, I know this isn't a comment about the comic, but I lust felt like tossing it in. And more relevant (possibly) was the fact that being the last semester the course was taught, the final exam questions were all inside computer programming jokes. [[User:MAP|MAP]] ([[User talk:MAP|talk]]) 21:55, 14 November 2020 (UTC)

Given that the grade to be manipulated is only the grade of the final exam of Cybersecurity (and therefore not the grade for the entire class), but the grade that it affects is the grade for the entire Game Theory class, that there is no reason not to collaborate, and that how "closeness" is calculated is unclear, the ideal solution is to set the grade of every Cybersecurity student who is not also a Game Theory student to 100, and set the grade of every Cybersecurity student who is also a Game Theory student to 100(100-a)/(125-a), where a is the percentage of Cybersecurity students who are also Game Theory students. This ensures all Cybersecurity students who are also Game Theory students get a perfect 4.0 GPA in Game Theory while reducing their Cybersecurity score by the smallest possible amount. [[User:DL Draco Rex|DL Draco Rex]] ([[User talk:DL Draco Rex|talk]]) 17:12, 15 November 2020 (UTC)
:There is a factor you haven't accounted for - hacking carries an implicit penalty in the form of effort expended; although I would like to think students will go to any amount of effort to get a good grade, I wonder whether that is realistic. [[Special:Contributions/141.101.98.124|141.101.98.124]] 15:38, 20 November 2020 (UTC)

I just have to say this for fans of the Dutch comedy show ''Rundfunk'': "ALLEMAAL EEN ONVOLDOENDE!" (Any more Dutch people around?) --[[User:IByte|IByte]] ([[User talk:IByte|talk]]) 13:34, 16 November 2020 (UTC)

I've been thinking that hack all grade at Cibersecurity to 100% or to the minimal approval grade, should get all students approved. Unlike the Guess 2/3 of the average problem, student don't need to hit the mark to be approved, they need only to get close enough. If everyone receives maximum grade in Cybersecurity, the average will be 100% and they will be off the 80% by 20%. Assuming some linearity between the transformations of distance and grade, and that grade cannot be negative. The longest distance from 80% of average would be everybody gets maximum grade, but one who get zero, it would get closer to 80% off, as long we have a lot of students in the class. Assuming 80% off zero grade, and 0% off as maximum, 20% off would get them 75% of maximum grade, that seems enough to get approval in both classes. --[[User:Hugoxrosa|Hugoxrosa]] ([[User talk:Hugoxrosa|talk]]) 19:33, 1 December 2020 (UTC)

I have heard that some cybersecurity tests either involve defending a network or attacking one, and your final grade was how successful you were.