What to do & see
GAZE AT THE CENTER OF THE ROTATING SPIRAL FOR ABOUT 37 SECONDS, THEN CONTINUE LOOKING AT THE NEXT IMAGES. YOU WILL NOTICE WHATEVER YOU LOOK AT NOW APPEARS SWIRLING. DON'T WORRY, IT WON'T STICK ?, THIS SENSATION WILL GO AWAY IN A FEW SECONDS.
GAZING AT THE SPIRAL FOR A LONGER TIME WILL INCREASE THE DURATION OF THE AFTEREFFECT, LEVELING OUT AT 40 S. HOLDING THE GAZE STEADY AT THE CENTER, DON'T OVER-CONCENTRATE, "LET IT HANG" ALSO INCREASES THE EFFECT.