In the episode where the two astronauts land on a planet with little people on it and one of the astronauts thinks he is a god to them, he starts to crush some houses. Notice that there are three houses with a tree behind the middle house. When he crushes the middle house the frame goes back to him, but then in the frame where he tries to crush the houses again you notice that the house on the right moves left to the middle and the tree moves to the right.