While you hold the crayon behind your back scrape a bit of the wax off
of the bottom of the crayon with your thumb nail. When you turn around
you hold your hand up to your head as though you are concentrating.
While pretending to concentrate, look at the color on your thumb and
guess correctly every time! Just, make sure the crayons are very different in color. You don't want to be trying to distinguish between two very similar shades of orange!