aims to reduce the overall number of drawings. Film is projected at 24 frames per second. For movements in normal speed, most animation in general is done "on twos," meaning each drawing is displayed twice, for a total of 12 drawings per 24 frames per second. Faster movements may demand animation "on ones" with a new drawing in each frame, while characters that do not move may be done with a single drawing (a "hold") for a certain amount of time. It is said[who?] that the Disney average was about 18 drawings per second, pretending that all characters of a scene share the same sheet of paper. Limited animation mainly reduces the number of inbetweens, the drawings between the keyframes which define a movement, and can cause stuttering if inbetweens are poorly set up.