Wanrumuwandoa

Wanrumuwandoa ("One Room One Door") is a logic puzzle published by Nikoli. A rectangular or square grid is divided into regions ("rooms"). A region may contain a cell with a number. The goal is to blacken some cells of a grid according to the following rules:

Wanrumuwandoa

Cross+A can solve puzzles from 3 x 3 to 30 x 30.