It works by taking a photograph of the object, then moving the object a little bit and then taking another photograph. After assembling the photographs to a film, it appears as though the objects would move by themselves. This is similar to the animation of cartoons and is used in many early monster films, like the [Ray Harryhausen]? and King Kong films and more recently in the works of [Aardman Animation]?s Wallace and Gromit films.