optical illusion

An optical illusion is a picture or a figure that deceives or confuses the eye and/or brain. Categorization of optical illusions is difficult because several underlying mechanisms may contribute to an effect, or the cause of the illusions may not be completely understood. See individual entries in the table below for details. See also anamorphosis.

Types and examples of optical illusions
type examples
distortion illusion Fraser spiral
Müller-Lyer illusion
Orbison's illusion
Poggendorff illusion
Titchener illusion
Zöllner illusion
impossible figures and objects Freemish crate
Penrose triangle
Penrose stairway
ambiguous figure Ames room
Necker cube
Schröder's reversible staircase
Thiery figure
lateral inhibition illusion Hermann grid illusion
antigravity houses and hills