# Tag Info

### How can 3 queens control the white squares?

I think this arrangement works for the bonus question:
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### How can 3 queens control the white squares?

I think this will do it
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### How did four chessmen disappear?

This seems to work: And the position looks like this: Apart from the symmetrical solution, this might very well be unique:
• 78.1k
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### Ernie and the Lock-down Puzzle

Ernie's jigsaw puzzle isn't as straightforward as it seems, as it's actually: One way of assembling the pieces legally is: How will you know when you have succeeded? PS Ernie definitely has a sense ...
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### A pentagon that can measure the first 7 integer distances

A possibly more elegant solution for 1..7 if we don't insist on a convex pentagon.
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You're
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### Most ways to uncheck the king

Eeny meeny myny moo (or however you want to spell that)
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### Consecutive captures on the same square

Since we are talking about a standard game of chess (although with both players co-operating), we know that there are four pieces that cannot possibly make a capture in the series: the two bishops on ...
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### Efficient Mowing at PSE

Proof of optimality for the solutions given
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### Mishustin's circle problem

Here's my go (click to embiggen) Steps: Connect A to P and pick an arbitrary point Q between them, near-ish to P. Then, draw lines as shown, constructing the points in alphabetical order, which ...
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The 'hardest' possible Irregular Sudoku has and it looks like this:
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### Chess Construction Challenge #6: The One Move Royale

Vepir has helped twice in this answer, first in spotting a mistake and then with an improvement in the number of moves. Please got upvote their answer too if you like this one. Here is a position with ...
• 138k

### Can you arrange 25 whole numbers (not necessarily all different) so that the sum of any three successive terms is even but the sum of all 25 is odd?

There are only two possible solutions (disregarding meaningless number swaps). Explanation What I mean by "meaningless number swaps"
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### Make exactly 101 squares using as few lines as possible

I can do it in lines.
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### What if I told you that guessing in Sudoku is very bad and might give you a bad karma?

Glorfindel's answer is sufficient for the main question. To answer the bonus question: Here is an example: To construct this example, As for a starting position,
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### A pentagon that can measure the first 7 integer distances

The answer is This can be proven by
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### Make exactly 101 squares using as few lines as possible

I'm hoping it's within the rules, but if so: It works for any number of squares! I'm unfortunately not familiar with any tools to generate an image for this, but the approach is: For a better ...
Accepted

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### The Game of Golden Squares

I've achieved tiles, and can prove that this is the optimal solution. Reasoning: Golly 4.0+ pastable RLE of this solution: ...
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### Create a 1 meter measure

I can do it in just: Initial configuration: First: We have: Now: We get the mark: Finally: You get: And the required distance is: Why this works:
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### What's the most distant chess position?

This question was asked on Chess Stack Exchange a couple of years ago: Which chess position requires the most moves to reach? Just like @loopywalt here in the comments, I remembered Tim KrabbĂ©'s diary ...
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### Make exactly 101 squares using as few lines as possible

I can match Lezzup's record of using only infinite straight lines: I'm pretty sure this is the minimum attainable, since For the record, Dudeney's version can be also solved with the same number of ...
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### Can you color the 8x8 grid red and blue?

Here is one way you can do it: Alternatively:
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### Can you color the 8x8 grid red and blue?

Some more fun solutions: Both satisfy the following self-imposed restrictions: Each row and each column contains exactly four blue and four red squares. The grid is symmetric in some way.
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### No moves at all, not even to put yourself in check

Here are my first idea (both sides are essentially the same answer, so the hint fits too): Both positions seem to be independently reachable by a legal game. It might be possible to find a legal game ...
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### Is there a configuration of the 8-puzzle where locking a tile makes it harder?

As far as I know, the only way to figure this out is by letting a computer run through all the possibilities. It is a small puzzle, so this does not take long. First I will assume that you want the ...
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### Chess Construction Challenge #6: The One Move Royale

Score: Position: Moves: Fun fact,
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