We don't know how they make these, but they're absolutely brilliant.
Just take a look at the image below and stare at it. If nothing's happening, get closer to your screen and try staring dead centre of the pattern.
Hold on, where did that pattern go?
Commenters on Sploid have been discussing the phenomenon, and the current consensus is that it's something to do with the colour-detecting cells in our eyes being overloaded with colour, and the brain attempting to correct the white balance to counter it. We'll be honest, we don't really follow that.
But anyway: cool, isn't it?