Sierpiński Fortress
(Published on 21. March 2026, 08:00 by Kaktuslav)
Rules: Normal sudoku rules apply. Fortress: Each grey cell is a fortress cell: its digit is greater than each orthogonally adjacent non-grey cell. XV: Cells separated by an X sum to 10. Cells separated by a V sum to 5. Not all possible Xs and Vs are given.
Solution code: Row 1
Comments
on 19. July 2026, 16:14 by guirigui
Wow, I found this one much harder than the usual Kaktuslav 3* puzzle... must have missed something!
on 24. March 2026, 15:31 by Klausku
Beautiful construction. Thanks!
on 24. March 2026, 11:20 by kasperd
Today I learned there is a fractal named the Sierpiński carpet. And the fortresses in this puzzle are roughly the complement of that fractal.
on 23. March 2026, 09:32 by Crusader175
Fun puzzle!
on 22. March 2026, 13:38 by Franjo
Thank you very much for creating and sharing another beautiful puzzle. Amazing setting!
on 21. March 2026, 19:51 by greemi01
enjoyable puzzle
on 21. March 2026, 13:15 by muule
I enjoyed the break-in and nice flow afterwards
on 21. March 2026, 10:40 by Elliott810
Beautiful puzzle! Thank you:)
