Café Wall

This now famous optical illusion was first observed in the tiles of the wall of a café.

Straight Lines Illusion

The Hering Illusion is an optical illusion discovered by the German physiologist Ewald Hering in 1861. The two vertical lines are both straight, but they look as if they were bowing outwards.

Bigger Arc Illusion

The bigger the better. Which arc is bigger? The Jastrow Illusion is an optical illusion discovered by the American psychologist Joseph Jastrow in 1889. In this illustration, the two figures are identical, although the lower one appears to be larger.

3D Discs

French artist Marcel Duchamp created these Rotoreliefs, discs designed to be placed on the turntable of a gramophone. When rotating, each disc creates an illusion of depth. The illusion becomes more intense when viewed with only one eye.

Longer Line Illusion

The Müller-Lyer Illusion is an optical illusion consisting of nothing more than an arrow.

Taller Line Illusion

This is one of many versions of the Ponzo Illusion, an optical illusion that was first demonstrated by the Italian psychologist Mario Ponzo.

Taller Trumpeter Illusion

This is another version of the Ponzo Illusion, an optical illusion that was first demonstrated by the Italian psychologist Mario Ponzo.

Phenakistoscope

The phenakistoscope (also spelled phenakistiscope) was an early animation device used to create the illusion of motion.

Square Circle Illusion

The Ehrenstein Illusion is an optical illusion studied by the German psychologist Walter Ehrenstein in which the sides of a square placed inside a pattern of concentric circles take an apparent curved shape.

Impossible Stairs Illusion

If going up stairs. These stairs will tire you out. The Penrose Stairs is an impossible object created by Lionel Penrose and his son Roger Penrose.

More Lines Illusion

The Zöllner Illusion is a classic optical illusion named after its discoverer, German astrophysicist Johann Karl Friedrich Zöllner.

Ambiguous Stairs Illusion

Proof that up is down and down is up. The Schroeder Stairs Ambiguous Figure was created by Heinrich Georg Friedrich Schröde

Pac-Man Illusion

Blast from the past? This optical illusion known as the Kanizsa Triangle was first described by the Italian psychologist Gaetano Kanizsa.

Flower Power

The Ebbinghaus Illusion is an optical illusion of relative size perception.

Necker Cube

The Necker Cube is named after the Swiss crystallographer Louis Albert Necker.

RR Tracks Illusion

Wrong side of the tracks. The Ponzo Illusion is an optical illusion that was first demonstrated by the Italian psychologist Mario Ponzo.

Which Lines Connect?

The Poggendorff Illusion is an optical illusion that involves the brain's perception of the interaction between diagonal lines and horizontal and vertical edges. It is named after Poggendorff, who discovered it.

Ball & Shadow Illusion

Is there ambiguity in the position of an object in space? Only the shadow knows. Where are the balls in space? See how shadow influences the perception of position.

Bulge Illusion

Do you see a bulge? This is a variant of the Hering Illusion, from Akiyoshi Kitaoka.

Liar

Liar, liar, pants on fire!

Leaning Tower Illusion

This illusion is best described as an visual rather than optical because the "trick" happens in the mind not the eyes.

Bar Code Animation

Barrier-grid animation, also known as a kinegram, and "picket fence" animation and often referred to by the genericized trademark "Scanimation", is an animation effect created by moving a striped transparent overlay across an interlaced image.

Impossible Triangle

The Penrose Triangle, also known as the Penrose Tribar, or the Impossible Tribar was first created by the Swedish artist Oscar Reutersvärd in 1934. The psychiatrist Lionel Penrose and his mathematician son Roger Penrose independently devised and popularized it in the 1950s.

Pulsating Snowflake

Gianni A. Sarcone designed this Pulsating Star illusion, based on the Müller-Lyer Illusion principle.

Checker Shadow Illusion

Edward H. Adelson, Professor in Vision Science at MIT, published this optical illusion in 1995.

Figure Ground +

Do you see black figures on a white background, or do you see white figures on a black background?

Ready for My Close-Up

A hybrid image is an image that is perceived in one of two different ways, depending on viewing distance. A technique for creating hybrid images was developed by Aude Oliva of MIT and Philippe G. Schyns of University of Glasgow.