Lost in the Modhouse II
(Published on 19. September 2026, 21:51 by KMD)
This is an unplanned sequel to a popular puzzle of mine from a couple years ago: "Lost in the Modhouse". The twist is this puzzle utilizes global modularity; a unintuitive and bizarre constraint I've invested entirely too much time on this past year, but this puzzle finally says everything I've wanted to with it. Let me know how you get along and happy solving.
SUDOKU
Place the digits 1-9 once each in every row, column, and 3x3 box.
Every 2x2 area of cells in the grid must have at least one digit from each of the following sets: (1,4,7), (2,5,8), (3,6,9).
DYNAMIC FOG
The grid is covered in fog. Placing a correct digit will remove the fog in that cell and possibly elsewhere.
DISJOINT CONSTRAINTS
Each of the following constraint types (A-D) must not contain a repeated digit anywhere in the puzzle (e.g., if a pink line contains a 5, then no other pink line in the puzzle may contain a 5):
A) Digits on a pink line form a consecutive set of digits in any order.
B) 3x3 box borders divide blue lines into segments of equal sums.
C) One digit is double the other in cells across a black dot.
D) The difference is a multiple of 3 between digits across a black diamond.
Solution code: row 9, left to right
Comments
on 28. September 2026, 12:56 by amirs
I definitely got lost in this Modhouse, that was tough!
on 22. September 2026, 15:43 by Arheus
That was brutal. But I loved it! 4*
on 21. September 2026, 10:49 by Snookerfan
Very nice and a real challenge! Global modularity is somehow harder to work with than global entropy. Thanks
on 20. September 2026, 11:54 by Bankey
Fun puzzle. Thanks, @ KMD :).
on 20. September 2026, 04:11 by emoney1374
Very good and very difficult puzzle!
Thank you for saying so! KMD
on 20. September 2026, 01:22 by palletpusher
Well this was delightful, KMD! I don't find global modularity particularly bizarre or unintuitive, and I really enjoy its interactions with the other constraints you chose.
It seemed like I may have deviated the intended solution path when I placed a forced digit and half a black kropki dot emerged from the fog on the cell's border.
Brilliant puzzle! 75 minutes for me
Thank you for solving. There is a redundant clue in the grid to make it easier to solve, so perhaps you managed the tougher road. KMD
