A visual Illusion that baffles adults and children even after they know how it's done. Two boomerangs, red and yellow are shown as being exactly the same size yet they appear to magically stretch, one at a time. The red one stretches longer then the yellow, then the yellow stretches longer than the red. Can be repeated as often as you want.

Volunteers can examine the parts and become audience participants. Just have the volunteer hold the parts, as below, and they are doing the magic. Even after they know how it's done, they are still amazed!!