Animation is the rapid display of a sequence of images of 2-D artwork or model positions in order to create an illusion of movement. It is an optical illusion of motion due to the phenomenon of persistence of vision. This could be anything from a flip book to a motion picture film.

Winsor McCay created detailed animations that required a team of artists and painstaking attention for detail. Each frame was drawn on paper, requiring backgrounds to be redrawn, as well characters to be animated. His films such as Gertie the Dinosaur (1914) and The Sinking of the Lusitania (1918) were of an impressive scale, although The Sinking of the Lusitania used cels.