The crater

What you can do here
Look closely at the pattern on the wheel and start spinning it gradually increasing the speed. What can you see? Experiment by rotating the disk with various angular velocities in both directions. At a certain slow speed, you will have the impression that the object is three-dimensional. If you don’t see the third dimension straightaway, look at the spinning disk for a while.


How it works
The sequence of lines and their thickness give an illusion of 3D. Thicker lines are interpreted as closer and thinner as more distant.
When you look at an object, both your eyes see a slightly different image which allows your brain to assess the distance. This mechanism is the basis of depth perception. This perception, however, is also possible with a single eye because of a number of phenomena that the brain uses to interpret images. Relative object sizes or shadows may play a part.


Interesting facts
The French artist Marcel Duchamp (1887-1968) used stereoscopy (an illusion of depth) in 1935 in spinning cardboard wheels called Rotoreliefs. Another of his works are presented in our exhibition as The Wandering wheel.