Choco Banana is a logic puzzle published by Nikoli. A rectangular or square grid contains numbers in some cells. The goal is to blacken some cells of a grid. An area of black cells must form a rectangle or square. An area of white cells must not form a rectangle or square. If a black or white area contains a number, it indicates the size of this area. An area may contain more than one cell with a number.
Cross+A can solve puzzles from 3 x 3 to 30 x 30.