Melting Pot
(Published on 18. September 2026, 07:23 by James B.)
Rules:
Place the digits 1-4 once each in every row and column.
Shade the grid using the following colors: Red, Blue, Green, and Yellow such that each color contains the digits 1-4 once each. Cells shaded with the same color must NOT be orthagonally connected.
Each color has an additional restriction. They are as follows.
Red: Red cells must be positioned at prime numbered cells (Top left cell is #1 Bottom Right cell is #16 read from left to right)
Blue: A digit in a blue cell indicates which row it is in. (Top row is row 1, bottom is row 4)
Green: The digit in green cells indicates the number of different colors beneath the cell in its column (including itself)
Yellow: I lied earlier about all the colors having additional restrictions. Nothing special about yellow.
Play PuzzleSolution code: Every cell on the grid in the order they appear. (Left to right top to bottom.)
Comments
on 22. September 2026, 17:19 by Yoshi Baroshi
Very neat logic behind! Quite a minimal ruleset as well, but a very elegant solve. Loved it!
on 22. September 2026, 02:45 by James B.
Also included a solution check on the puzzle in Sudokupad.
on 22. September 2026, 02:42 by James B.
Updated the link and rules on this page to include the updated version of the rules such that they are clearer.
on 21. September 2026, 13:35 by PjoeterBliep
Quite tricky for a 4×4, lovely!
on 21. September 2026, 04:48 by The Pi Guy
Magnificent puzzle. The link could do with changing so that the rules are correct (the ‘to the’ needs removing) but the solve path is a thing of beauty. Thank you for sharing it. ❤️
Please let me know as soon as you’ve updated the link and I will recommend it to others. :)
James B: Thank so much for the feedback and for solving the puzzle, I would be grateful for you to recommend it to others! And I did update the rules to not include the error in the rules.
on 19. September 2026, 23:23 by The Pi Guy
Hi James. Could do with clarification of what the rule involving the green cells means as the rules aren’t at all clear. For example, does it mean the whole of the column where that cell is down to the cell itself and no further? The rule probably needs rewording so it makes any kind of sense.
James B: Sorry for the confusion. The Green rule should read "A digit in a green cell indicates the number of different colors beneath the cell in its column(including itself.)"
Strange I didn't catch that myself, error came from an earlier stage of the puzzle when green was referencing the digits to the right of itself in its row.
on 18. September 2026, 17:39 by James B.
Spaced out some parts of the rules to make it more legible
on 18. September 2026, 10:29 by XhcnoirX
Very nice, I didn't expect this to have such a cool logical flow!
James B: Thank you!
