Editing 2496: Mine Captcha

{{comic
| number    = 2496
| date      = July 30, 2021
| title     = Mine Captcha
| image     = mine_captcha.png
| titletext = This data is actually going into improving our self-driving car project, so hurry up--it's almost at the minefield.
}}

==Explanation==
{{incomplete|Created by a LIVE MINEFIELD WITH HUGE NUMBER CUBES STREWN AROUND. Please mention here why this explanation isn't complete. Do NOT delete this tag too soon.}}

This comic, like [[1897: Self Driving]], references the approach of using {{W|CAPTCHA}} inputs to solve problems, particularly those involving image classification that computers need to know how to solve. Specifically, it reflects {{W|reCAPTCHA}} v2's fallback puzzle which is based on identifying road features and vehicles. A reCAPTCHA puzzle might ask a user to "check all squares containing a STOP SIGN" in order to help train systems that must do it automatically.

This is actually a trick captcha. It asks to click on '''pictures''' of mines. There are no pictures of mines in the captcha, there are only numbers and empty fields.

{{w|Minesweeper (video game)|Minesweeper}} is a logic puzzle game where the player must uncover tiles in a grid by clicking on them. Some of the tiles contain "mines" such that revealing those means immediate defeat. When uncovering a tile without a mine it shows how many of the (up to 8) adjacent tiles contain a mine or, if the tile has no neighbouring mines, it automatically and recursively reveals every neighbouring tile as far as all numbered 'clue' tiles. By reference to the indications provided by those numbers, a player (optionally, but typically) will mark those that they identify in their efforts to succesfully reveal all unmined locations and win the game having tripped none of the mines.

This comic uses the game to create a CAPTCHA that ironically asks the user to "Click all the pictures of MINES", the opposite of the traditional goal, hence the title Mine Captcha.

This mine CAPTCHA might be considered awkward for a variety of reasons. Firstly, unlike image recognition, which is a natural biological and developmental skill, humans don't naturally learn the tricks needed to win at Minesweeper. It is a logic game {{w|Microsoft Minesweeper|being bundled with Microsoft Windows}} which provides little obvious instruction and often it was bored people launching the program who would start randomly clicking on squares unsure of what they are supposed to do. Those who perservere get to learn the tricks and traps, but not everyone will do that and thus also understand how to adequately solve the CAPTCHA.

Secondly, clicking on the squares that contain mines is the opposite of what you do in actual Minesweeper, and players who are sufficiently familiar with the game might get tripped up by muscle memory, putting you at a disadvantage no matter your skill level with the original game.

Thirdly, Minesweeper involves a certain degree of luck. While logical skills are important, there are possible instances (increasingly so as the chosen difficulty level is increased) where the numbers do not provide adequate information to confidently assure it is in a single specific square, leaving even expert players to have to guess and hope they do not trip on one of the more unlikely (but possible) final mines after a lot of other mental work done to successfully clear and confirm the rest of the map. If luck plays any part in the CAPTCHA, this would increase false negatives in human detection. (The implication of most logic puzzles is that the problem given to the user is of a state where only one possible solution exists as an answer, but the conceit of this one is that the solution is ''not'' known by the puzzle-creator.)  [https://pragmada.x10hosting.com/mindet.html "Mine Detector"] is a variant game which provides better information, such that it's almost always solvable without guessing except at the highest difficulty level.

Fourthly, solving a game of Minesweeper is usually (although not in this case) impossible without clicking more of the empty gray squares to reveal enough info to figure out which ones have mines on them.

Fifthly, a CAPTCHA is meant to be a challenge designed to be solvable by humans but not computers; Minesweeper would be easily solvable by an AI (assuming no ambiguity) as it is, at its core, a logic puzzle, and the squares are simple shapes with solid-color backgrounds and thus relatively easy for an AI to process.

Regarding the game itself, 6 of the 16 tiles have a colored number, in blue for the three number ones, green for a single instance of two, and red for the two number threes. Given the current board configuration, one can deduce that there are four mines (in squares A2, B2, B3 and D3, where letters (numbers) mark columns (rows)), see [[#Trivia|trivia section]]. For example, there are two mines within the squares A2,B1,B2, as signified by the 2 in A1, but only one of those can be in B1 or B2 (because of the 1 in C1). Therefore, A2 has to be a mine.

Each number is shown in a different font and style.  This follows a technique used in CAPTCHAs that display text in various styles, often distorted, and ask the user to type in the displayed characters.  

The title text is similar to [[1897: Self Driving]] where the CAPTCHA solver is asked to answer quickly, parodying the current tendency for CAPTCHAs to apparently be used as training data to teach AI how to correctly identify road hazards by instead suggesting the CAPTCHA offloads the task to a human instead. In this case the car is apparently driving into a minefield and can only avoid the mines if the user solves this CAPTCHA fast enough. Where the first would be plausible, although very dangerous, this time it hinges on ridiculous, as real minefields usually do not have large numbers indicating which of the surrounding land contains mines{{citation needed}}.

==Transcript==
:[A Minesweeper game in a 4x4 grid is shown beneath a blue rectangle. There is an explanation in white text in the blue field:]
:To proceed, click all the pictures of '''<big>Mines</big>'''

:[The ''Minesweeper'' field has six cells with revealed numbers on a light gray background. The other 10 fields are empty and dark gray. The three ones are blue, the single two are green and the two threes are red. On top of this each number is drawn in a different font/style. The ones changes how bold they are. The two is drawn in a 3D format, the one three is very thin and the other is drawn with two lines and no filling in between (hollow). The grid looks like this:]

 <font color="green">2</font> . <font color="blue">1</font> .
 . . <font color="red">3</font> .
 <font color="red">3</font> . . .
 . <font color="blue">1</font> . <font color="blue">1</font>

==Trivia==
*The solved version of the puzzle showing where the mines are in this comic, and thus the fields that needs to be pushed in this Captcha to prove you are human:
:[[File:2946_Mine_Captcha_With_Bombs.png]]
*The solved puzzle as it would look if played as a real minesweeper game, except the mines would be represented by flags. (The empty square top right corner has 0 bombs next to it. This is not written in the game but indicated as this field has been pushed down):
:[[File:2946_Mine_Captcha_Solved.png]]
*The original game can be played here: [https://minesweeper.online/ World of Minesweeper]
**It is possible to build a 4x4 CAPTCHA game there:
:[[File:2946_Mine_Captcha_Example_of_4x4_game.png]]

{{comic discussion}}

[[Category:CAPTCHA]]
[[Category:Self-driving cars]]
[[Category:Comics with color]]
@@ Line 8: / Line 8: @@
 ==Explanation==
+{{incomplete|Created by a LIVE MINEFIELD WITH HUGE NUMBER CUBES STREWN AROUND. Please mention here why this explanation isn't complete. Do NOT delete this tag too soon.}}
-This comic, like [[1897: Self Driving]], references the approach of using human-entered {{w|CAPTCHA}} inputs to solve {{w|machine learning}} problems, particularly those involving image classification.
+This comic, like [[1897: Self Driving]], references the approach of using {{W|CAPTCHA}} inputs to solve problems, particularly those involving image classification that computers need to know how to solve. Specifically, it reflects {{W|reCAPTCHA}} v2's fallback puzzle which is based on identifying road features and vehicles. A reCAPTCHA puzzle might ask a user to "check all squares containing a STOP SIGN" in order to help train systems that must do it automatically.
-In order to prevent automated programs from using web services, Google offers a protection called {{w|reCAPTCHA}}, which performs various tests to see if a user is human or machine. One of these tests is a "I'm not a robot" checkbox which must be checked in order to proceed, although ticking the box is merely a formality, and later versions of reCAPTCHA can simply perform the tests quietly in the background without needing user consent.
+This is actually a trick captcha. It asks to click on '''pictures''' of mines. There are no pictures of mines in the captcha, there are only numbers and empty fields.
-If the reCAPTCHA system suspects that the user may be an automated bot, it presents an image recognition challenge that only humans should be able to pass. This has the desired effect of denying access to robots, but it also has a side benefit that the human input can be used to train Google's image recognition software. The challenge usually features a square grid of images, typically things one might see while driving - e.g. "Check all squares containing a stop sign". If the user clicks enough correct squares, they are permitted to continue.
+{{w|Minesweeper (video game)|Minesweeper}} is a logic puzzle game where the player must uncover tiles in a grid by clicking on them. Some of the tiles contain "mines" such that revealing those means immediate defeat. When uncovering a tile without a mine it shows how many of the (up to 8) adjacent tiles contain a mine or, if the tile has no neighbouring mines, it automatically and recursively reveals every neighbouring tile as far as all numbered 'clue' tiles. By reference to the indications provided by those numbers, a player (optionally, but typically) will mark those that they identify in their efforts to succesfully reveal all unmined locations and win the game having tripped none of the mines.
-{{w|Minesweeper (video game)|Minesweeper}}, on the other hand, is a logic puzzle game in which the player is presented with a grid of unrevealed squares and must deduce the location of mines that have been secretly hidden on random squares. The game provides clues by marking some squares with the number of mines (up to a maximum of 8) that are adjacent to that square; by carefully considering the possibilities, a player can deduce which squares must contain mines, and mark them with flags to avoid clicking on them. Revealing a mine loses the game.
+This comic uses the game to create a CAPTCHA that ironically asks the user to "Click all the pictures of MINES", the opposite of the traditional goal, hence the title Mine Captcha.
-In this comic, Randall combines the two concepts to create a "Mine Captcha", which is presented in the form of a reCAPTCHA challenge but actually appears to be a mini game of Minesweeper. To be more precise, it is actually the ''opposite'' of regular Minesweeper. This challenge invites the user to click on the mines, as opposed to Minesweeper's aim of clicking only upon unrevealed squares that are ''not'' mines. Furthermore, within the terms of a reCAPTCHA, there are no ''pictures'' of mines displayed, to click upon. This is also the case for Minesweeper, as they only appear once the game ends, all remaining hidden during play and thus needing to be deduced where they all are.
+This mine CAPTCHA might be considered awkward for a variety of reasons. Firstly, unlike image recognition, which is a natural biological and developmental skill, humans don't naturally learn the tricks needed to win at Minesweeper. It is a logic game {{w|Microsoft Minesweeper|being bundled with Microsoft Windows}} which provides little obvious instruction and often it was bored people launching the program who would start randomly clicking on squares unsure of what they are supposed to do. Those who perservere get to learn the tricks and traps, but not everyone will do that and thus also understand how to adequately solve the CAPTCHA.
-A real-world Mine Captcha would be somewhat ineffective for a variety of reasons. Firstly, not every human would recognize a game of Minesweeper and therefore wouldn't understand what they are being asked to do. Even if they do recognize the game, they may not know the logical method for deducing the locations of mines. Additionally, even for skilled players, there is a trap in that the Captcha's objective is the reverse of regular Minesweeper; they might therefore get tripped up by muscle memory and click on something that is not a mine, which would fail the challenge.
+Secondly, clicking on the squares that contain mines is the opposite of what you do in actual Minesweeper, and players who are sufficiently familiar with the game might get tripped up by muscle memory, putting you at a disadvantage no matter your skill level with the original game.
-Another issue is that games of Minesweeper can sometimes involve a degree of luck, as it is possible to generate a puzzle which does not give sufficient information to unambiguously deduce the location of every mine. This may not be a problem since Randall's Minesweeper is only a four-by-four grid. In these situations, the most a player can do is click the uncertain square and hope for the best. If the Mine Captcha is poorly implemented in this way, this would increase false negatives in human detection due to some humans failing the captcha purely due to bad luck. Some variants attempt to eliminate this problem: ''[https://pragmada.x10hosting.com/mindet.html Mine Detector]'', for example, is a variant game which provides better information, such that it's almost always solvable without guessing except at the highest difficulty level.
+Thirdly, Minesweeper involves a certain degree of luck. While logical skills are important, there are possible instances (increasingly so as the chosen difficulty level is increased) where the numbers do not provide adequate information to confidently assure it is in a single specific square, leaving even expert players to have to guess and hope they do not trip on one of the more unlikely (but possible) final mines after a lot of other mental work done to successfully clear and confirm the rest of the map. If luck plays any part in the CAPTCHA, this would increase false negatives in human detection. (The implication of most logic puzzles is that the problem given to the user is of a state where only one possible solution exists as an answer, but the conceit of this one is that the solution is ''not'' known by the puzzle-creator.)  [https://pragmada.x10hosting.com/mindet.html "Mine Detector"] is a variant game which provides better information, such that it's almost always solvable without guessing except at the highest difficulty level.
-Finally, a Mine Captcha would actually be fairly easy for an artificial intelligence to solve, since it is a logic puzzle: as long as the AI can read the numbers, it can simply use an algorithm to eliminate all impossibilities until it has the correct answer. With a 4x4 grid it's even easier than that: a computer could quickly brute force the problem by trying every possible arrangement of mines until it has the correct one.
+Fourthly, solving a game of Minesweeper is usually (although not in this case) impossible without clicking more of the empty gray squares to reveal enough info to figure out which ones have mines on them.
-It seems that Randall predicted that an AI might try to solve the captcha itself, as he rendered each numeral in a different style; this is similar to obfuscation methods used in text-based captchas to prevent automatic text recognition software from reading the captcha. However, it would not be very effective in this case as the same numbers have the same color; an AI could simply recognize the color instead, which is even easier for an AI than trying to read a number.
+Fifthly, a CAPTCHA is meant to be a challenge designed to be solvable by humans but not computers; Minesweeper would be easily solvable by an AI (assuming no ambiguity) as it is, at its core, a logic puzzle, and the squares are simple shapes with solid-color backgrounds and thus relatively easy for an AI to process.
-The title text is similar to [[1897: Self Driving]] where the CAPTCHA solver is asked to answer quickly, implying that the training data is actually a real-world situation being experienced by a self-driving vehicle at that very moment. The joke here is that real-life minefields do not have large numbers indicating which of the surrounding land contains mines{{citation needed}}.
+Regarding the game itself, 6 of the 16 tiles have a colored number, in blue for the three number ones, green for a single instance of two, and red for the two number threes. Given the current board configuration, one can deduce that there are four mines (in squares A2, B2, B3 and D3, where letters (numbers) mark columns (rows)), see [[#Trivia|trivia section]]. For example, there are two mines within the squares A2,B1,B2, as signified by the 2 in A1, but only one of those can be in B1 or B2 (because of the 1 in C1). Therefore, A2 has to be a mine.
-==Solving the Mine Captcha==
+Each number is shown in a different font and style.  This follows a technique used in CAPTCHAs that display text in various styles, often distorted, and ask the user to type in the displayed characters.
-Assuming that columns are denoted by letters A, B, C, D, left to right, and rows are denoted by 1, 2, 3, 4, top to bottom, one way to solve the captcha is as follows:
-The leftmost red 3 at A3 is surrounded by four squares (A2, B2, B3, A4), of which we know three are mines. Therefore, one of these squares is not a mine. However, because of the blue 1 at B4, we know that only one of B3 and A4 can be a mine, otherwise, there would be more than one mine adjacent to B4; therefore, '''A2''' and '''B2''' ''must'' be mines. Otherwise, there could only be two total mines adjacent to A3.
+The title text is similar to [[1897: Self Driving]] where the CAPTCHA solver is asked to answer quickly, parodying the current tendency for CAPTCHAs to apparently be used as training data to teach AI how to correctly identify road hazards by instead suggesting the CAPTCHA offloads the task to a human instead. In this case the car is apparently driving into a minefield and can only avoid the mines if the user solves this CAPTCHA fast enough. Where the first would be plausible, although very dangerous, this time it hinges on ridiculous, as real minefields usually do not have large numbers indicating which of the surrounding land contains mines{{citation needed}}.
- <font color="green">2</font> . <font color="blue">1</font> .
- <font color="violet">X X</font> <font color="red">3</font> .
- <font color="red">3</font> . . .
- . <font color="blue">1</font> . <font color="blue">1</font>
-Since A1 is a green 2 and is adjacent to two squares that we now know are mines (A2 and B2), this means that B1 is ''not'' a mine. If it was, there would be 3 adjacent mines to A1. Furthermore, since there is a blue 1 at C1, and we know that the adjacent B2 is a mine, this means that D1 and D2 are also ''not'' mines, since if any of them were, there would be more than one mine adjacent to C1.
- <font color="green">2</font> <font color="gold">O</font> <font color="blue">1</font> <font color="gold">O</font>
- <font color="violet">X X</font> <font color="red">3</font> <font color="gold">O</font>
- <font color="red">3</font> . . .
- . <font color="blue">1</font> . <font color="blue">1</font>
-We also know that C3 and C4 are ''not'' mines, since we already know that the blue 1 at B4 is next to exactly one mine (on either B3 or A4). Since this eliminates two of the three possible neighbors of the blue 1 at D4, this means that '''D3''' ''must'' be a mine.
- <font color="green">2</font> <font color="gold">O</font> <font color="blue">1</font> <font color="gold">O</font>
- <font color="violet">X X</font> <font color="red">3</font> <font color="gold">O</font>
- <font color="red">3</font> . <font color="gold">O</font> <font color="violet">X</font>
- . <font color="blue">1</font> <font color="gold">O</font> <font color="blue">1</font>
-Finally, since we now know the locations of two of the mines around the red 3 at C2, and we have eliminated all other possibilities, '''B3''' ''must'' be a mine. Therefore, the mines are at '''A2''', '''B2''', '''B3''', and '''D3'''. This solves the puzzle.
- <font color="green">2</font> <font color="gold">O</font> <font color="blue">1</font> <font color="gold">O</font>
- <font color="violet">X X</font> <font color="red">3</font> <font color="gold">O</font>
- <font color="red">3</font> <font color="violet">X</font> <font color="gold">O</font> <font color="violet">X</font>
- <font color="gold">O</font> <font color="blue">1</font> <font color="gold">O</font> <font color="blue">1</font>
 ==Transcript==
@@ Line 72: / Line 46: @@
 ==Trivia==
-*The solved version of the puzzle showing where the mines are in this comic:
+*The solved version of the puzzle showing where the mines are in this comic, and thus the fields that needs to be pushed in this Captcha to prove you are human:
 :[[File:2946_Mine_Captcha_With_Bombs.png]]
-*The solved puzzle as it would look if played as a real minesweeper game, except the mines would be represented by flags. The empty square top right corner has 0 bombs next to it. This is not written in the game but indicated as this field has been pushed down:
+*The solved puzzle as it would look if played as a real minesweeper game, except the mines would be represented by flags. (The empty square top right corner has 0 bombs next to it. This is not written in the game but indicated as this field has been pushed down):
 :[[File:2946_Mine_Captcha_Solved.png]]
 *The original game can be played here: [https://minesweeper.online/ World of Minesweeper]