Hey, George, that's a cool illusion! I'd never seen that before.
I'm guessing that it's related to afterimages. I suspect that the green dot
is the afterimage of the pink dot, more or less. I'll bet that when the
afterimage combines with a screen image of a fixed pink dot, the effect is
to produce the neutral background grey. I noticed that the disappearance of
the fixed dots is rather precarious, and depends on keeping my eyes a
constant distance from the screen, and keeping my gaze very fixed on the
cross. I suspect that very good 'registration' is required.
I'll bet that the phenomenon called 'persistence of vision' is being
exploited here, too, but I know next to nothing about it.
That's neat.
Hey, on a related note - has anyone seen O'Meara's "Haidinger's Brush"?
I've tried like heck to see that thing and I get bupkes [sp?].
Marek Cichanski
Received on Sun Oct 30 13:54:13 2005