How about a mystery in front of your own eyes? Look at this picture.
Do you see three faces? If not, try again!
You should be able to see the face of a man with a bushy moustache, an old lady with sunken cheeks, and the side profile of a young girls face.
This image is a classic example of an optical illusion. An optical illusion is nothing but tricks that the brain and eye play on us!
Now if that sounds weird, lets get more scientific. An optical illusion occurs when our eyes see certain things and the brain perceives something different. The two combined bring forth extraordinary images, which we term optical illusions.
Lets try another one. Take a five-inch square piece of paper. Tape two opposite sides together so that the paper forms a tube.
Now take the tube in your right hand. Hold it up to your right eye and look through the tube, keeping both eyes open.
Put your left hand, fingers up, palm toward your face, up against the left side of the tube. Your palm should be about two-thirds of the way down. Notice that you see a hole in your hand!
One eye sees a hole, the other eye sees a hand. Your eyes and brain add the images together, creating a hand with a hole!