Douieru (from Japanese, literally "same and different") is a logic puzzle invented by Nishiyama Yukari (Japan). A rectangular or square grid contains circles in some cells. The aim is to divide the grid into L-shaped regions. The two "legs" of a region must be exactly one cell wide. A circle represents a cell in which an "L" must bend (the grid contains circles for all regions). If a cell contains a double circle, the two legs of the region must have the same length. A black circle means difference in leg lengths. If a cell contains a white circle, the ratio of leg lengths is unknown.
Cross+A can solve puzzles from 3 x 3 to 30 x 30.