The Rotating Dots illusion – Pink fades to Grey & Green appears
This is one of my favourites. It relies on the fading that occurs within the eye, when we fix our gaze upon an image.
Stare fixedly at the central cross.
The circle of Pink dots with a rotating gap, will gradually change to a single Green dot, rotating against a uniform Grey background.
The only Green component in this image is the Green component of the Grey background. As the rotating ring of Pink dots fades to Grey our brain misinterprets it as a single rotating Green spot, where in reality there is Grey.
It works for other colours too, see: Various Coloured Dots
When the Pink dots have faded, while keeping your gaze fixed in the centre, try varying your viewing distance from the screen.
The book
