I quite often get forwarded these sort of things. I have always found them really fascinating.
So I thought that I would share them with you:
1. What do you see?
Relax and concentrate on the 4 small dots in the middle of the picture for 30 seconds.
Then, take a look at a wall near your (any,smooth single color surface).
You will see a circle of light developing,
Start blinking a few times and you will see something emerging…
2. Concentric Circles