The animation that is looped above right provides an example of a homotopy between two embeddings, "f" and "g", of the torus into . "X" is the torus, "Y" is , "f" is some continuous function from the torus to "R"3 that takes the torus to the embedded surface-of-a-doughnut shape with which the animation starts; "g" is some continuous function that takes the torus to the embedded surface-of-a-coffee-mug shape. The animation shows the image of "h""t"("x") as a function of the parameter "t", where "t" varies with time from 0 to 1 over each cycle of the animation loop. It pauses, then shows the image as "t" varies back from 1 to 0, pauses, and repeats this cycle.