[Pete.]

• Illusion named Benham's top after Essex-born toymaker Charles Benham
• Some people see green, a few yellow or red and other see no colour at all
• Exactly why illusion looks different to different people is still a mystery
• Benham's top is being researched for use as a tool to identify eye disease

Stare at this black and white wheel long enough and you may see a colour appear out of nowhere.

But incredibly, different people see different colours - and some may not see anything at all.

Many people say they see green, others see yellow and a few see red, but exactly why this is the case has baffled scientists for decades.

The wheel is called Benham's top and it creates an illusion of colour when black and white patterns rapidly change, as reported by Casey Chan on Sploid.

It is named after the Essex-born toymaker Charles Benham, who, in 1895, created a top painted with the pattern shown.

When the wheel is spun, arcs of subtle colour, called Fechner colours, are visible at different areas on the surface.

I'm colour blind I can only see black and white :{}