White is black, or is it...
At first glance, it appears to be a black and white chess board with a green cylinder casting a shadow diagonally across the board. However, the black and white squares are simply different shades of grey. The 'white' squares underneath the shadow (including 'B') are actually exactly the same shade of grey as the 'black' squares outside (including 'A'). This is known as the Adelson Checker Shadow Illusion.