Bagatelle  Brain  Teaser
If your eyes follow the movement of the rotating pink dot, you will only see one colour, pink.

If you stare at the black
+ in the centre, the moving dot turns to green.

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

It's amazing how the brain works. There is no green dot, and the pink ones don't really disappear.

Just goes to show, we don't always see what we think we see!