Sherlock Jr’s “movie within a movie”: The scenery changes around Buster Keaton very quickly. He suddenly finds himself in a doorway to a garden, on a crowded city street to on top of a rock, etc. Keaton later recalled that his cameraman, Byron Houck, had used surveying instruments to position him and the camera at the exact correct distances and positions to give the illusion of continuity as the scenes changed. Long before CGI, Keaton created a vivid world with its own laws.