Typically, two glass slides, one with the stationary part of the picture and the other with the part that was to move, would be placed one on top of the other and projected together, then the moving slide would be hand-operated, either directly or by means of a lever or other mechanism. https://psychology.avije.org......AC/
The name "film" originates from the fact that photographic film (also called film stock) has historically been the medium for recording and displaying motion pictures. Many other terms exist for an individual motion-picture, https://military.avije.org......85/
Traditionally, films were recorded onto celluloid film through a photochemical process and then shown through a movie projector onto a large screen. https://military.avije.org......87/