How to play
Every cell is either solid or outlined. A number counts how many of the cells directly above, below, left and right are unlike it. Diagonals don’t count.
3
The solid 3 has three outlined neighbours, so three cells are unlike it. The fourth matches.
- Tap a cell to cycle it: blank, solid, outlined.
- A gold dot marks a pinned cell. It’s set for you and can’t change.
- Every board has exactly one solution, and you can always reach it without guessing.
- On a keyboard: arrow keys move, Space cycles, S or O sets a cell, Backspace clears.