Suguru ("Number Blocks") is a logic puzzle invented by Naoki Inaba (Japan). The task consists of a rectangular or square grid divided into regions. Each region must be filled with each of the digits from 1 to the number of cells in the region. Cells with the same digits must not be orthogonally or diagonally adjacent.
Cross+A can solve puzzles from 3 x 3 to 30 x 30.