3 major optical illusions are literal, physiological & cognitive.
Literal - create images that are different from the objects that make them
Physiological - effects on the eyes and brain of excessive stimulation of a specific type, eg brightness, colour, size, position, tilt and movement
Cognitive - resulting from unconcious inferences
|Do you see the side or front image of a man?|
Oh, fun fact 101 - girls can register optical illusions faster and more at ease than boys. :)
Source of text: Wikipedia
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