 For instance, the 16-omino in the form of a 4 × 4 square and the 18-omino in the form of a 3 × 6 rectangle are both equable.For polyominoes with fewer than 15 squares, the perimeter always exceeds the area.In recreational mathematics, challenges are often posed for tiling a prescribed region, or the entire plane, with polyominoes, and related problems are investigated in mathematics and computer science.