Double Choco is a logic puzzle published by Nikoli. In a rectangular or square grid exactly half of cells are painted gray. The aim is to divide the grid into regions. Each region must contain one area of white cells and one area of gray cells. A pair of areas must be of the same shape and size (the areas may be rotated or mirrored). A number indicates how many cells of the same color the region contains. A region may contain more than one cell with a number (in this case the cells contain the same number).
Cross+A can solve puzzles from 4 x 4 to 30 x 30.