Optical Illusions Activity Cards

Julia is obsessed with these Optical Illusions activity cards (buy here). She uses them during car rides, and she even takes them to school to show her friends. These cards feature mind-bending illusions to surely surprise your child. They are taken from a personal collection of Al Seckel, who is a world expert on visual illusions. An optical illusion on each card is accompanied by a question, and a text on the reverse side explaining how the illusion works in tricking the eye.  "How many feet does the elephant have? Does the gray bar in the middle gets gradually darker? Can you find three faces? Are the two table tops a different size and shape? How many prongs does the fork have? Do you see a triangle? Can you find both an old and a young women on the picture?"

These two people look angry. Can you make them smile?

Do your children use activity cards?