Illusion

[firstfrost]

This is the coolest optical illusion I've seen yet:

http://www.patmedia.net/marklevinson/cool/cool_illusion.html

Comments

[firstfrost.livejournal.com]

There's two things going on.

First, the appearance of the green dot is pink green afterimageness. If you stare at a non-moving pink dot for a bit, and then look elsewhere on the screen, you'll see a green dot afterimage.

Second, our eyes are good at edge detection and its friend motion detection. If you can force yourself to stare at a fixed point anywhere (which is really hard), you'll notice that your vision starts greying out. We naturally move our eyes around a lot. So the pink dots are fading out because everything fades if it doesn't move, and they fade particularly hard because they have no edges.

[chenoameg.livejournal.com]

Not only do they have no edges, but I'm pretty sure the background grey was carefully chosen to appear the same to our non-color vision. I bet that helps them disappear.

(Hmm, what a neat form of secret message, something that you could only see after you let the pink dots disappear...)

[jaedian.livejournal.com]

wow, that is TOO cool.

And if you do it and then look up abit, you see the whole ring of green dots as after images. I did anyway.

[merastra.livejournal.com]

Yeah, me too. I saw the ring of green dots afterwards.