Colour illusions

Spinning wheels

Benham's top

When this disc is spinning colours appear. You should be able to see colours such as blue, green and a dull red. The generally accepted explanation for this illusion is based upon the view that our retinas contain substances which are predominantly sensitive to red, green or blue light. The repeated pulses of black and white stimulate the red, green and blue visual systems differently thus creating an illusion of colour.