The above image may appear to be waving and composed of parallelograms, but it is actually made up of squares.
Akiyoshi Kitaoka, Professor, Department of Psychology, Ritsumeikan University, Kyoto, Japan, studies visual perception and optical illusions. A favorite subject is the "anomalous motion illusion", in which our visual system is provided contradictory information causing apparent motion when there is none.
Check out professor Kitaoka's website for a dizzying array of visual illusions.
WARNING: Viewing these illusions might make sensitive observers dizzy or sick.