Modropic Lines
(Published on 15. December 2025, 19:49 by GraphZahl81)
Standard Sudoku rules apply: Every row, column, and 3x3-box contains the digits 1-9 exactly once.
A digit in a grey cell is
- smaller than all digits in orthogonally adjacent cells if the arrows point inwards,
- larger than all digits in orthogonally adjacent cells if the arrows point outwards.
Every line in this puzzle is both entropic and modular: Any set of three consecutive cells on a line contains a small digit (1,2,3), a medium digit (4,5,6), a large digit (7,8,9), and a digit from each of the sets (1,4,7), (2,5,8), and (3,6,9).
Cells with a V between them contain digits whose sum equals 5.
Solution code: The diagonal from top-left to bottom-right (9 digits)
Comments
today, 00:03 by Reina
The revelation of consequences of both entropic and modular for lines longer than 3 cells hit me like a truck! Love it!
on 20. December 2025, 06:04 by Fisherman
I would appreciate a mini series of this modropic rule.
Answer: This comment inspired me to create a second one: 000QMR.
on 18. December 2025, 01:49 by PinkNickels
Was able to solve in <10 minutes, but I've learned the secret of this ruleset the hard way in the past. Very nice setting. Hopefully, those new to this rule set can find the secret! Thanks for sharing
on 16. December 2025, 07:28 by GraphZahl81
Thanks for the comments, adapted the difficulty rating.
on 16. December 2025, 02:00 by BorisTheSnake
Definitely a very easy 1* if you understand the modularity/entropic rules. Was fun though, thanks! :)
on 15. December 2025, 20:52 by superkinkel
Nice one, however after the break in, everything resolves quite quickly. Maybe a two star in the beginning, but one you've figured it out, it's quick. The modropic line is quite a powerful constraint.
