[Note: nonstandard attribution layout.]
Beryl wrote:
Entertaining thread this turned into. Anyway, here's a nice illusion.

http://img408.imageshack.us/img408/8067/imagegm1.gif

Concentrate on the + in the middle.
An illusory green dot soon appears.
Moments later, pink dots seem to disappear.

Very interesting and neat.

cavelamb himself wrote:
I'll repost this one here - so it's easier to find?
HEHEHE!

http://www.sonnyradio.com/spinninglady.html

It took some doing, but by glancing to one side (and sometimes briefly
closing my eyes and trying to imagine the reverse spin) I was able to
switch the perceived rotation direction. However, I have it on good
authority that I do not have an IQ of anywhere near 160. :-)

A couple times I had a shift in perceived rotation direction without
looking away.

cavelamb himself wrote:
I think this one is awesome.
Can these really be the same color???

http://www.home.earthlink.net/~cavel....htm#samecolor

Hard to believe indeed. I decided to do an image copy from the browser and
pasted the copy into the MS Windows Paint program. Copied two square chunks
of each of the two labeled board squares and pasted them side-by-side. Sure
enough they are the same color.