Initializing live version
Requires a Wolfram Notebook System
Interact on desktop, mobile and cloud with the free Wolfram Player or other Wolfram Language products.
The red circles have the same radius. However, their sizes seem to vary, depending on the sizes of the blue circles. This illusion was first discovered by Franz Joseph Delbouf, a Belgian philosopher and expert on hypnosis.
Contributed by: Michael Schreiber (March 2011)
Open content licensed under CC BY-NC-SA
Wolfram Demonstrations Project
Published: March 7 2011