[img] 
[/img]
I've got a headache now.
UhOh. Found it!
[img] 
[/img]
That us crazy! When I look directly at it there's none, but when I look at the edges there's loads. Now I'm seeing then everywhere. Time for a lie down...
The marvels of lateral inhibition, there is no black dot!
it's here >>>>> .
man, make it stop!
It's in the middle of the word 'dot'
I is confused. No black dots for me wherever I look. Are my eyes broken?
boojum
What is worse is that when you print out the picture there are still black dots moving round on the paper.
Never mind that! Stare at the red dot for 30 seconds, then look away at a blank wall.
[img] 
[/img]
Holy crap CFH that's weird! Why!? How does that work??????
Persistence of vision, innit.
[img] 
[/img]
Oh wow, I've learned something amazing from, this thread - there exists a [url= http://hilobrow.com/2012/09/26/paleo-gifs/ ]theory[/url] that states cave paintings with multiple heads or legs appeared animated when viewed with flickering firelight.
"Lascaux is the cave with the greatest number of cases of split-action movement by superimposition of successive images. Some 20 animals, principally horses, have the head, legs or tail multiplied. When the paintings are viewed by flickering torchlight, the animated effect “achieves its full impact,” said Azéma."
