Naked Angels on Bikes
Naked Angels on Bikes is a product by Paul Harris which uses the angels on the back of a Bicycle brand playing card. One card is kept under the clear cellophane of the card case to protect it from outside forces. When removed, one of the angles moves (leaving just a weird blank space where it was) to join the other angels riding together side by side.
See also another product by Paul Harris using the angels on the back of the cards called Cardian Angel.