Trinairo is a logic puzzle invented by Leo de Winter (Netherlands). The objective is to fill a 9 x 9 grid with letters so that each row and each column contains three letters A, three letters B and three letters C. If a cell is marked with other color, a letter in the cell differs from letters in all orthogonally adjacent cells.
Cross+A can solve puzzles 6 x 6, 9 x 9 or 12 x 12.