If your eyes follow the movement of the rotating pink dot, you will only see one color, pink.
(Of course there's not really any movement, it's just one dot after another disappearing.)
Now, if you stare at the black plus sign (+) in the center, the "moving" dot turns to green!
Howdy doodat?
If you continue to concentrate on the plus sign, all the pink dots will gradually disappear,
and you will only see a green dot rotating! (Whoa! How's that possible?)
Interesting how the brain works. There really is no green dot, and the pink ones really don't disappear.
No, it's not HTML wizardry - your brain supplies the illusion all on its own.
This should be proof enough (if any more were needed) that
we don't always see what we think we see.