1 square piece of corrugated cardboard (the kind with open tubes inside), about 5 1/2 inches square
1 wooden skewer (the thinner the better)
1 rubber band
2 pieces of Styrofoam, about 2 inches long and thick enough to fit tightly in the hole of a CD
TIP: If you don’t have any Styrofoam… Try out different materials in place of the Styrofoam. Get creative and use other things around the house to hold the wheels in place—old marshmallows, pieces of dry sponge, packing material, gummy candy, layered masking tape, etc. Try them all and see what makes your wheel work best!