Can you paint a 10x10 grid with 3 colours such that it doesn't contain any rectangles whose corners are all the same colour? Computers are allowed :)
A similar question about 2 colours is here: Painting a 4x6 grid with 2 colours
Good luck!
In the spirit of the What is a Word™/Phrase™ series started by JLee, a special brand of Phrase™ and Word™ puzzles.
If a word conforms to a special rule, we call it a BORE Word™.
Use the examples below to find the rule.
$$\begin{array}{|c|c|}\hline
\bbox[yellow]{\textbf{BORE Words™}} & \bbox[ye...
This is in the spirit of the What is a Word/Phrase™ series started by JLee with a special brand of Phrase™ and Word™ puzzles.
If a word conforms to a special rule, I call it a STATE Word™.
Use the following examples below to find the rule.
$$\begin{array}{|c|c|}\hline
\bbox[yellow]{\textbf{STAT...
Researchers from Ecuador knocked down an important obstacle in the road to a complete understanding of the human mind. "The initial plan to map specific areas of the human brain is 95% complete", Dr. Ecay, head of the team says. "We have found that the frontal lobe is especially attuned to the...
This is in the spirit of the What is a Word/Phrase™ series started by JLee with a special brand of Phrase™ and Word™ puzzles.
If a word conforms to a special rule, I call it an MM Word™.
Use the following examples below to find the rule.
$$\begin{array}{|c|c|}\hline
\bbox[yellow]{\textbf{MM Wor...
Ten Quotas. Nine Passed. Your Turn
This puzzle is part of the "Piece de Resistance" series. Go back to Part 1 (Ace) for the story.Ace Two Three Four Five Six Seven Eight Nine Ten...
Hmm... this is... a comic strip??
I'm currently stuck on this puzzle from Simon Tatham's website (he calls it "Unequal", although the standard name according to Wikipedia is Futoshiki). My progress so far is:
I've even tried a few "what if" conditions (assuming another cell is filled in a particular way, and seeing what can be...
I present to you all a highly interesting problem that I came across awhile ago on Tim Krabbe’s site.
It’s White move and win, i.e. reach a winning positon, in 21 moves.
Source: David Gurgenidze & Velimir Kalandadze, Shakhmaty v SSSR 1975, 2nd Prize
You may only use your own brain power! Goo...
A set of line segments inside or at the edge of a square with side length 1 should be positioned in such a way,
that any straight line going through the square must touch or intersect at least one of the line segment.
Find such a configuration where the total length of all such line segments is ...
It's been a whiiiiiile since we've had one of these!
You continue on through the forest and enter the labyrinth, once more. And again, you find a small piece of paper: 73-86-85-53-6-7
There's also a fairly futuristic keyboard lying on the ground. You guess that you must type in a passphrase i...
Following on from a hard (and currently unanswered) puzzle here, we have this easier but still interesting selfmate in 5.
This is a puzzle by A. Rubin found in The Book of Extraordinary Chess Puzzles:
From the book: "In a 'selfmate' problem White plays to force Black to checkmate him -...