This was pretty cool, so decided to post here:

1: If your eyes follow the movement of the rotating pink dot, the dots will remain only one color, pink.
optical illusion
2: However if you stare at the black ” + ” in the centre, the moving dot turns to green.

3: Now, concentrate on the black ” + ” in the centre of the picture. After a short period, all the pink dots will slowly disappear, and you will only see only a single green dot rotating.

It’s amazing how our brain works. There really is no green dot, and the pink ones really don’t disappear. This should be proof enough; we don’t always see what we think we see.

[Thanks to Shruti and Mayank who originally sent it to me!]