I think it's an illusion of an illusion - keep track of one dot - note how it goes a full circle - starts at 12 o'clock, then 1, 2 3 'o'clock etc as it does a circle. The dots are actually rotating in a circle. I think it's a furphy and not an illusion....what you see is actually white dots moving in a circle within the large orange circle. The site says "you may think you see a circle of eight white dots rotating around the inside of a larger red circle" Also watch each ball as it travels along the straight line - it moves from one side of the line to the other in a wave pattern...not a straight line. There is no illusion - at least that's the way I see it.
Always question!
Edit....I thought long and hard as to whether I should question this on the GN forum because I don't want to be seen as someone saying "there's a mistake". Sorry but that's the way I've been reading things.
And please note that I say "I think' - not "I know".
-- Edited by hako on Monday 1st of December 2014 11:26:29 PM
Hako, Don't know if there's a problem with your display or mine but I see the white circles consistently bisected by the line on which it travels and the white circle moves from one side of the large, orange circle to the diametric opposite and back again - so it repeatably moves between, for example, 10 o'clock and 4 o'clock in a straight line and the other small circles do the same although on different axis. The combination of the eight balls moving along different lines at different starting times creates the illusion of circular motion.
I can understand that Dave, but try putting your cursor on one of the dots and it goes round the circle of dots and follow it's motion, the dot moves in a circular motion around the centre of the dots - possibly it's how you interpret: "you may think you see a circle of eight white dots rotating around the inside of a larger red circle"
