The coolest optical illusion ever

Okay, I'm not kidding, this has got to be the coolest optical illusion ever.

Make sure GIF animation is turned on, and click here.

Stare at the cross in the center for a bit.

Isn't that cool? The ring of purple dots sorta fades, and you just seen a green dot going around!

But there's no actual green in the image! Look directly at the purple dots and you can see the complete lack of green. But the animation still fools your mind into thinking its there...

Spiffy, eh?