In this activity from Fetch! you will create an optical illusion toy called a thaumatrope. A thaumatrope demonstrates a theory called persistence of vision. A thaumatrope has two images. When it spins, it moves so fast that your brain holds onto both images and merges them into one. You spin the thaumotrope using rubber bands. Winding them up creates stored or potential energy. Letting them go releases energy and turns it into motion, or kinetic energy.