Motion After Effect

Aristotle is reported to be the first person to ever report on seeing a stationary object move AFTER having watched a constant movement.

The neurons of the eyes will adapt both to a static image, as in the after effect phenomena, and to motion. This is easily explained that neurons that have been firing repeatedly will be less likely to fire as often when a stimulus has been removed.

See the Illusion

This was a very difficult illusion to recreate, and the result, when you see it, can be quite subtle.

Concentrate on the moving symbols in the graphic below for about a minute. At the end of a minute, stop the graphic from moving, in internet explorer by clicking on the Stop button, and with Firefox by clicking on the window boarder.

You'll need to wait for 5 to 10 seconds your eyes to calm down from all that motion, and then you should see the blocks either start floating up, or elongating upwards very slightly.