There are many optical illusions, both natural and man-made, that can trick your brain… every time. The visual illusions are characterized by visually perceived images that differ from objective reality. The information your eyes gather doesn’t match the source in some way, causing a major (awesome) headache.
There are three main types of illusions: “literal optical illusions that create images that are different from the objects that make them, physiological ones that are the effects on the eyes and brain of excessive stimulation of a specific type (brightness, colour, size, position, tilt, movement), and cognitive illusions, the result of unconscious inferences.”
These 2 blocks are the same color. … … Cover the line with your finger to check.
Stare at the cross for 10 seconds … … the purple dots disappear.
Find more at http://www.viralnova.com/instant-optical-illusions/