How to play Napdoku

Napdoku is a logic puzzle on a patchwork quilt. The board is split into colored patches, and your job is to tuck sleepy critters in so that nobody wakes anybody up.

Rule 1: one critter in every row and column

Each row and each column of the quilt holds exactly one sleeping critter. On a 7×7 board that means seven critters, one per line.

Rule 2: one critter on every patch

The quilt is split into colored patches, and each patch gets exactly one critter, too. Patches differ in pattern as well as color, so the board stays readable for color-blind players.

Rule 3: critters never touch

Two critters may not sit in neighbouring cells, side by side or diagonally. If they touch, they wake each other up.

Rule 4: logic only, no guessing

Every Napdoku board has exactly one solution, and a program checked that you can always reach it by reasoning.

Controls

Tap a cell once to put a cross where no critter can sleep, and tap again to tuck a critter in. Swipe across cells to cross out many at once. Every move can be undone, and there are no hearts or lives to lose.

Hints that teach

Stuck? A hint first points out a mistake on the board, then explains the next logical move in one sentence. The Sleepyhead School teaches the six main tricks on small boards.

How it differs from Sudoku

There are no numbers and no math. As in Sudoku, every row and column gets exactly one of something, but here the colored patches and the no-touching rule do the work.