My uncle is the email-forward-expert in our famly. Some of the emails that he sends, though, are mind boggling. I would like to share the following optical illusion with you all.
Concentrate on the rotating dot, you will see the dots, pink in colour. Focus on the black ‘+’ sign in the middle, and you will see the pink dot change to green. In reality, there is no green colour in the picture. Wow.
Mouli's blog 
Terrific.
How does this happen? What makes us see green?
I have no idea. The little I know is that, the fast moving dots create an optical illusion in the retina, causing it to send confusing signals to the brain, which tells you about the green.
I think this is similar to the illusion with complementary colors. If you stare at a red circle on a neutral field, e.g. gray, and then look at white paper, you will see a green circle, its complementary color. Remember that red/green, yellow/violet, and blue/orange use the same receptors, which is why some people are blind to these pairs of colors.
Here is a website with more info: http://hyperphysics.phy-astr.gsu.edu/hbase/vision/rodcone.html
Catherine
Thanks Catherine for the link. And thanks for visiting.
You’ve got it slightly wrong. You can “see” the green dot just from watching it. Focus on the + in the center for a while & all the pink dots disappear. THAT’S the cool part!
Ah. I see that now. Thanks Lana for pointing that out.
Welcome to my site, and thanks for visiting.
That is really cool!
very nice page…let me add my 2 cents to this blog by sharing a really good gallery of optical illusions
at http://appslog.com/blog/1-blog/836-optical-illusions-what-you-see-is-not-what-you-get.html
I have seen a lot of optical illusions, but this is one I have not seen before. It is really great.
Concentrate on the rotating dot, you will see the dots, pink in colour. Focus on the black ‘+’ sign in the middle, and you will see the pink dot change to green. In reality, there is no green colour in the picture. Wow.