Optical illusions can occur naturally or be demonstrated by specific visual tricks. There are three categories of illusions:
These animations will test your senses! Although these balls seem to go in opposite directions, they go in the same direction and at the same speed!
In this image you can see the face of a young woman, and that of an old lady.
Look closely at the elephant image, it seems to be all right but something is not right: the animals' legs are twice and even where they should not be there!
Illusion of three-dimensionality!
Spin the wheel to where?
Look at the picture for about 30 seconds ... Then try to look at your hand!