The Café Wall Illusion was first described by British psychologist Richard Gregory and his research assistant Priscilla Heard in 1979
The café wall illusion is a geometrical-optical illusion where straight dividing lines between staggered dark and light blocks appear to be curved. The theory is that our brains determine a white area to be larger than a black area, when it is actually the same size (known as the irradiation illusion). This can be proved by swapping black and white colours for any other colours with lower contrast.
