Shikaku (also known as "Divide by Squares", "Divide by Box", "Number Area") is a logic puzzle. It is played on a rectangular grid. Some of the cells in the grid are numbered. The objective is to divide the grid into rectangular and square pieces such that each piece contains exactly one number, and that number represents the area of the rectangle.
Cross+A can solve puzzles from 3 x 3 to 30 x 30.