Apparent Movement
One of the earliest techniques 
for creating apparent motion 
was the "magic disk."  The 
figures appear to move when 
the disk is spun in front of a 
mirror and the figures’ 
reflections are viewed through 
one of the narrow slits in the 
disk.  Many people believe that 
the effect is based on the visual 
persistence of one picture as 
successive pictures are seen.  
This explanation, however, 
would only explain the absence 
of flicker, not the perception of 
motion.

Most people realize that moving 
pictures, including television, 
are illusions based on a 
succession of still pictures 
projected on a screen. But many 
believe that the illusion results 
from the eye’s tendency to 
continue to transmit signals to 
the brain from a frame of film 
even when it is no longer 
projected on the screen, thus 
filling the gap between frames. 
However, such persistence of 
vision explains only the 
absence of flicker, not 
apparent motion.