The Cafe Wall Illusion causes black and white tiles arranged in parallel horizontal lines to appear to twist and angle out of order. We have produced an interactive demo where you can play with several parameters and explore the resulting effects.
Mouse X: Displacement
Mouse Y: Grout Width
Left click: Cycle through five grout colors
Right click: Cycle through three displacement modes
As an interesting side note, we have noticed that when moving the mouse down and up rapidly (expanding or contracting the grout spaces), the tiles themselves appear to contract and expand respectively. This is an illusion, as the tiles are always the same size.