Using this picture as a guide, draw two circles that are about 4 1/2 inches in diameter. Cut a sheet of light cardboard the same size and shape; tape the wheels on opposite sides of the cardboard circle. At the x's on the top wheel, punch holes with an ice pick or large needle. Use crayons or paint to decorate the wheels, as shown in color key. Thread two 28-inch-long pieces of string through the holes and then through large buttons (which serve as handles) and tie the ends. To operate the wheel, whirl it around and around until string is well twisted. Now pull out slowly so that the wheel begins to spin in the opposite direction. Continue to pull out and release to keep the wheel spinning.