The phi phenomenon is a perceptual illusion (first described in 1912 by Max Wertheimer) in which a succession of still images produces a disembodied perception of motion. "Phi Phenomenon is astonishing precisely because its object is so familiar, and it fascinates me because it is a motion picture in which there is movement but no apparent movement." --Thom Andersen
[Source: Restoring the Los Angeles Avant-Garde: Thom Andersen and Morgan Fisher Program Notes, 2009]