If you take 5 squares of the same size and join them edge to edge, the resulting shape is called a Pentomino! There are more than 2000 ways to arrange the 12 different plastic puzzle pieces to form a rectangle. Includes 6 sets, one each in Red, Blue, Green, Yellow, Orange and Purple. Each of the sets includes 12 pieces that are scored in 1" sections. Helps to develop spatial-perception and geometry skills. Grades 1-9.