Follow the instructions.
1.- Click on the link below
2.- Then "click me to get trippy",
3.- Look at the center of the screen for at least 30 seconds (no cheating), and then
4.- Look at your hand holding the mouse, without moving it away from the mouse.
You'll be shocked at what you see.
( it is called "cenesthetic hallucination")
http://www.neave.com/strobe/