A geometry board is a simple peg board that can be used by kids (and adults) to experiment with shapes by simply stretching rubber bands around a grid of nails. My daughter asked me to make one for her and the entire job took about 30 minutes from start to finish.
Here's what you'll need to make a geometry board:
My daughter set the size for this board which is 7" x 7" x 3/4" with 36 nails spaced one inch apart. Start by measuring with a tape measure and making a pencil mark at 7" from the edge. If you have a table saw, rip the board lengthwise.