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Illusion - Qualified Perceptions
firstfrost
firstfrost
Illusion
This is the coolest optical illusion I've seen yet:

http://www.patmedia.net/marklevinson/cool/cool_illusion.html
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Comments
ricedog From: ricedog Date: October 21st, 2005 09:59 pm (UTC) (Link)
Oh no! We're still in the Matrix!

The coolest part is the way the pink dots disappear in the right sequence.
pekmez From: pekmez Date: October 21st, 2005 10:09 pm (UTC) (Link)
I want more explanation. If I cover up everything on the screen but
one pink dot, I see it turning green instead of getting more intensely
pink once per revolution. I can still believe that the pink-green thing
is related to weird eye afterimages, but I want to know what's going on.
firstfrost From: firstfrost Date: October 21st, 2005 10:14 pm (UTC) (Link)
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 From: chenoameg Date: October 21st, 2005 10:26 pm (UTC) (Link)
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 From: jaedian Date: October 21st, 2005 10:43 pm (UTC) (Link)
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 From: merastra Date: October 22nd, 2005 08:42 pm (UTC) (Link)
Yeah, me too. I saw the ring of green dots afterwards.
6 comments or Leave a comment