Abstract: A system for creating projected visual motion effects for filming or videotaping, with the use of still projection equipment, involves projecting a still image on a screen from a slide projector, projecting a second image on the screen, superimposed on the first image, and causing the projected second image to move rectilinearly at a controlled variable speed and in a selected direction over the first projected still image. This movement is accomplished with a "crawler" assembly having a transparent rectilinearly movable carrier panel carrying the second image over the stage surface of a standard overhead projector, or a light box, constituting the second image light source. The illuminated second image is directed to the screen by an overhead lens and suitably angled mirror. The transparent carrier is driven by a variable-speed reversible motor through a changeable worm gear drive assembly coupled to friction drive rollers engaging the carrier, which is slidably supportingly retained in a guide frame.