Bodaburokku ("Border Block") is a logic puzzle published by Nikoli. A rectangular or square grid contains numbers in some cells. It is necessary to divide the grid into regions. Cells with the same number belong to the same region. All points where three or four lines meet are given. Every region contains at least one cell with a number.
Cross+A can solve puzzles from 3 x 3 to 30 x 30.