Get fairly close to your monitor and stare into the center of the picture below for at least 60 seconds. Then quickly find an object in the room. Stare at it and watch it begin to move and expand in size.
Stare into the center of this object for at least 60 seconds. Then find another object in the room and stare at it. The object will appear to be breathing in and out.
This mind bender makes you see dots that aren't really there. Not only can you see the blue boxes, but you should also see gray dots in the corners of each box. But the dots only exist in your mind.