Yokibunkatsu (from Japanese, literally "container dividing") is a logic puzzle invented by Naoki Inaba (Japan). A rectangular or square grid contains stars in some cells. The goal is to divide the grid into regions of exactly five cells. Each region contains a star. The cells of the region must be foldable to a cube, with the star at the bottom and without the top side ("roof"). Some sections of borders between regions have already been given. The grid may contain cells that belong to no one region.
Cross+A can solve puzzles from 3 x 3 to 30 x 30.