These plastic geoboards are brightly colored and sturdy. The 9" square board features 121 pins, arranged in an 11 x 11 pin grid (numbered 0-10.) The reverse side features 137 pins arranged in alternating rows of 10 and 11. This arrangement allows for the easy formation of triangles, hexagons, etc. The 6" square board has a 25-pin (5 x 5) grid on one side, and a circle on the opposite side with one pin in each corner of the board (outside the circle) and one pin in the center of the circle. The geoboards come in a variety of colors; if you order more than one, we will assort. Includes rubber bands. ~ Rachel P.