A dynamic fog Sudoku exploring Fermat's theorem on the sum of two squares
Fermat's "Sum of Two Squares" theorem states that any odd prime number, p, can be written as the sum of the squares of two integers, A and B:
p = A² + B²
if and only if p ≡ 1 (mod 4).
This means that when divided by 4, p has a remainder of 1 (for example, if p = 13, then 13 ÷ 4 = 3 with remainder 1).
Normal Sudoku rules apply.
Have Fun Solving!
Lösungscode: Column 1, top to bottom.
am 10. April 2026, 21:17 Uhr von Neonesque
I love a good mathematical theorem.
am 25. März 2026, 22:39 Uhr von MattJones
Coo idea, some nice logic in there. Good fun!
am 19. März 2026, 21:36 Uhr von dzamie
That was a lot of fun! I admittedly kept worrying that I might run into a 3-digit number at some point, and only after the puzzle was over did I check to see that that would've been impossible (only 117 is reachable with single-digit squares, and 1 can't be orthogonally next to itself).
I would recommend, as a personal preference, that you not reveal the entire rest of the board in one go. Going from a lot of grey fog cells to instantly all white cells kinda flashbanged me for a moment.
am 17. März 2026, 20:38 Uhr von Cassinii
Fingers crossed
am 17. März 2026, 20:34 Uhr von Cassinii
Trying to centre the "p = A^2 + B^2" text
am 17. März 2026, 19:56 Uhr von Cassinii
Hopefully last one
am 17. März 2026, 19:52 Uhr von Cassinii
More HTML testing, sorry about the comment spam :(
am 17. März 2026, 19:47 Uhr von Cassinii
Trying to move the link!
am 17. März 2026, 19:38 Uhr von Cassinii
Testing stuff :)
am 17. März 2026, 16:05 Uhr von Prepared Jester
Very nice puzzle! I did have to grab pen and paper for a little help lol
am 17. März 2026, 14:13 Uhr von Rab3aron
Very beautiful puzzle!
am 17. März 2026, 11:38 Uhr von Cassinii
Please ignore these, I'm not changing anything!
am 17. März 2026, 11:36 Uhr von Cassinii
small changes
am 17. März 2026, 11:29 Uhr von Cassinii
text change
am 17. März 2026, 11:27 Uhr von Cassinii
Added link