Engineer's Nightmare How many impossible objects can you find in this fantastic engineering drawing? How many outlandish specifications do you see? There are 3 impossible rings, 1 impossible square, and the Devil's Trident. Can you identify all five objects? Feel free to submit this plan to ...

A language as familiar as English is ripe for ambiguity and design. There are powerful wizards among us who can manipulate the symmetry of familiar words. We revere these wizards and call them Typographers. The most powerful Typographers can weave letter forms into fantastic illusions. John ...

The rectangle on the left is mostly surrounded by white. The rectangle on the right is mostly surrounded by black. Which rectangle appears lighter? Use the slider bar to move the rectangles back and forth. As the rectangles overlap you see that they are identical. Colors appear lighter when they ...

The illusions in this section are driven by the way we see things such as high contrast and color. We have many specialized light receptors, but only a few million of them are active at any one time. Nearby, just out of focus, other receptors are at rest, or may be recovering from just being used. ...

howing a tourist sitting on a wall in an impossible angle at the Mystery Ridge, Oscoda, Mich. Showing two visitors standing at impossible angles at the Oregon Mystery Spot. Spook Hill is located at Lake Wales, Florida, near the Singing Tower Mountain Sanctuary. Stop on white line, take ...

The Moon Illusion This is only a demonstration, or representation of the actual lunar illusion in nature. For that you would need the real Moon and Sky. However it is a fairly accurate thumbnail of how the Moon might appear in the night sky.  In this demonstration the Moon follows a from ...

What is the Moon Illusion? It is often hard for an observer on earth to judge the true size of the Moon. The Moon may look bigger or smaller depending on where in the sky we see it in the sky. Most observers will say the Moon looks bigger when it is close to the horizon, and smaller or normal when ...

This is only a representation of the actual Moon illusion, and is not the actual illusion itself. However it is a fairly accurate thumbnail of how the Moon might appear in the night sky. In this demonstration the Moon will follow your mouse from low on the horizon to a point high in the sky. The ...

Fading Color Dots Stare directly at the cross in the center of this demonstration until you see a green dot appear under each fuzzy purple dot. The green dot is an afterimage. It only exists in your mind's eye. This program does not make them. Keep staring at the cross until the fuzzy dots begin ...

There is a delay of about one 10th of a second between the moment we "see" something, and the time when we actually visualize that something; due to brain processing time.  A simple experiment, invented by vision scientist Romi Nijhawan in the 1990s, called the Flash-Gap Experiment, allows us to ...

This window frame looks like it is swinging back and forth. But it's not a window at all, and it is actually rotating in complete circles! The window frame is really a flat card with a "picture" of a window painted an each side. The card is shaped like a trapezoid, and made to look like a real ...

We look for differences in texture, color, and light when we try to pick objects out of a background jumble. When there are little or no visual differences between the object we seek and the background colors and textures we are apt to have trouble seeing the object. The image on the left is an ...