This mind-bending optical illusion has left people scratching their heads - with two sums of money hidden among the spirals ...

In particular, a distortion known as 'Thatcherization ... pages 937–942 4. There's a great optical illusions website which has a rotatable online version of the original Thatcher image 5.

An illusion is an inaccurate perception of a real external object, indicating a sensory distortion. The most common illusions are visual, auditory, or tactile in nature, although smell and taste ...

Optical illusions aren't just fun brain teasers ... leading to a misinterpretation or distortion of reality. These visual ...