So, look at the circle of pink dots and follow the movement round. Unremarkably, you see the dots as the colour pink.
But now fixate on the +, and you should notice the 'moving' dot turns green! Pretty nifty, eh?
But there's more! Keep concerntrating on that + my Padawan learner, and I bet you can make all those pink dots completely disappear...
I love me a good Friday illusion to kick off the weekend.