Color the patterns to reveal eye-popping optical effects! Watch these amazing optical illusions materialize in front of your very eyes as you color them in! Aimed at compulsive doodlers and colorers of any age, this book contains 40 stunning illusions with keys to the hues that produce the most striking effects. Full-color renderings of each design at the back serve as a guide and as inspiration, and you can use any kind of medium from felt tips, paint, and marker pens to simple pencil shading to create a feast of color and movement.