Have you ever wondered what the visuals look like on hallucinogens? This isn't far off (um, I've read). This is not an animated gif, and nothing is actually moving. It's all in your head. Your trippy, trippy head.
Sadly, I do not know who created this incredible optical illusion — I lost the trail somewhere in the bramble of the internet. But whomever he or she is deserves high praise. You can focus on one swirl and it's stationary, but the other swirls in your periphery start to undulate and twist. Switch to another one, and the same thing is repeated. It's exquisitely executed. I should warn, however, that if you're actually on acid, you will either see nothing moving at all, or the effect will be so powerful that your mind will turn to tapioca. Consider yourself warned.
Click for the image below for the full-sized version.