The Benheim disc is named after the English toymaker Charles Benheim. In 1895, he sold a lid painted with this pattern. When the disc is turned, different arcs of pastel colours become visible.

This optical illusion is created by the flickering of the pattern during rapid rotation. Different people perceive different shades of colour.

The phenomenon of the Benheim disc is only partially understood. One explanation for the illusion of colour is that the colour receptors in the human eye react differently to red, green and blue.
The colour illusion is triggered by nerve activity in the retina and spatial interactions in the primary visual centre (visual cortex), where pattern recognition is processed.

The Benheim disc as well as similar patterns are used in the diagnosis of eye diseases and visual impairment, especially in optic neuritis.