OMG. I just realised. o_o I thought that if you stared at the center of the image the man was going to appear out of no where. xD;
I'm not surprised, it is a rather hard one to spot. Took me about 20 minutes to find him myself.
Here's another one:
Look at this wheel
closely. If you observe it carefully, you can actually make it spin both sides. No, this isn't an animation alternating between spins, it's yet another optical illusion based on your perception. Try actually
thinking that the thing is spinning clockwise/anti-clockwise if you're having problems following the thing.
Source =
http://www.moillusions.com/