Stop motion is an animated-film making technique in which objects are physically manipulated in small increments between individually photographed frames so that they will appear to exhibit independent motion when the series of frames is played back as a fast sequence. Dolls with movable joints or clay figures are often used in stop motion for their ease of repositioning. Stop-motion animation using plasticine figures is called clay animation or "clay-mation". Not all stop motion; however, requires figures or models: stop-motion films can also be made using humans, household appliances, and other objects, usually for comedic effect. Stop motion using humans is sometimes referred to as pixilation or pixilate animation.