Impossible Triangle

Ames' Window
A perspective illusion. A perspective-shaped window appears to change the way it rotates; moving round first in one direction then `flipping' to another and changing in size.

Cafe Wall
Distortion Illusion

Rows of light and dark tiles appear wedge-shaped, depending on the brightness of the mortar between the tiles. This tells us a lot about how we see edges.

Crescent Illusion
Identical crescent shapes appear to be different sizes.

Devil's Fork
A fork with two or sometimes three points.

Escher's Ladder
A reproduction of Escher's 'Belvedere' (Lithograph 1958)

Escher's Stairs
An illusory picture by M C Escher.

Expanding Spiral After-effect
The opposite effect to Shrinking Spiral After-effect.

Ghostly Circles
As Ghostly Triangles above. We often interpret gaps in an object as a `real' object.

Ghostly Triangle
We often interpret gaps in an object as a `real' object. This illusion illustrates a useful visual mechanism for recognising objects when only part is visible.

Ghostly Triangle 2
We often interpret gaps in an object as a `real' object. This illusion illustrates a useful visual mechanism for recognising objects when only part is visible.

Grey Ring Illusion
A grey ring covers an area one half of which is black, the other white. The part of the grey ring seen against the black appears lighter than that against the white when the two halves are separated by a line.

Herman Grid
A grid of black squares shows ghostly grey patches at the intersections.

Hollow Faces
Hollow face-masks sticking in appear to be faces sticking out showing that the brain's assumption of `all noses stick out' is difficult to overcome.

I only have eyes for you
A hollow Charlie Chaplin mask - his eyes appear to follow you as you walk past.

Impossible Triangles
Three lengths of wood are joined at two places. When viewed from a certain angle, eye and brain join them up in a triangle, even though the pieces of wood do not actually join up. What we know is sometimes at odds with what we see.

Jumbo Mumbo
A curious drawing of an elephant which sometimes has an extra leg.

MacKay's Rays
A pattern of radiating black and white lines produces colours and a jazzy swirling effect, due in part to after images in the eye.

Magic Wand
Persistence of vision explains why you see a picture when a wand is waved in the beam of a projector.

Moving Dots After-effect
Shows how the eye adapts to a rotating image.

Muller-Lyer Illusion
Two same-length lines appear to be different lengths.

Ponzo's Figure
Objects placed on converging lines appear to be different sizes. (The railway lines illusion.)

Sandpaper Illusion
Rub one hand on fine sandpaper, the other on coarse. When both then rub medium it feels different to each hand.

Shrinking Spiral After-effect
Gives an illusion of an expanding image showing adaptation to a shrinking pattern.

Size-Weight Illusion
Have you ever picked up what you thought was a heavy bag of shopping, and nearly fallen over when it only contains light cereal packets? This exhibit shows that we anticipate that large objects will be heavier than small, and when this is not the case applied too much force.

Skeleton Cube
A wire cube is rotating. It appears to flip and to reverse direction. But this does not look `right'. Why not?

Titchener's Circles
The size of circles surrounding a central circle affects our perception of its size.

Up-down Face
This face, drawn by the artist Rex Whistler, changes its character when turned upside-down to another face.

Wall of Illusions
This picture has many features giving it perspective. When you place shapes on different parts, they appear to be different sizes.

Vase or faces?

What Do You See?- Vase or Face
This is a familiar illusion - is the picture a vase or two silhouettes? When the same picture in the eye can be produced by different objects the brain has to decide which is correct.

When is a Square not a Square?
A square appears distorted when placed on a pattern of concentric circles.

Wobble Cone
A large disc painted with black and white circles appears to be a three-dimensional cone and to wobble as it rotates. Why is this?

Young or Old - or Both?
A famous picture which can either be an old or young woman's face.

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