Handimania has created an awesome tutorial video that demonstrates how to draw a fun 3D optical illusion of your hand. All you need is paper, a pencil, and some colorful markers. With the pencil, trace the outline of your hand and a bit of your wrist. Then, using a marker, draw a straight line from the edge of the paper to the edge of the outline. Next, draw a curved line over the hand, and draw another straight line to the edge of the page. Repeat until you have a stripey optical illusion!