This is without a doubt one of the coolest PC illusion I have seen so far. Follow the instructions:
1) Relax and concentrate on the 4 small dots in the middle of the picture for about 30-40 seconds
2) Then, take a look at a wall near you (any smooth, single coloured surface)
3) You’ll see a circle of light developing
4) Start blinking your eyes a couple of times and you will see a figure emerging
5) What do you see? Moreover, who do you see?
