The author first saw Trevor Fletcher's film on the cardioid as an undergraduate in 1959. When he saw Fletcher's cardioid film once again, the author was vividly reminded of his first experiences of animated mathematics nearly 50 years before. He discovered that the idea of using mental pictures to develop dynamic images came from work by the Swiss mathematics teacher Jean Nicolet. It was then taken up by early ATM members, influenced by Caleb Gattegno (1963). Later, the name "imaginings" was used by members of "Leapfrogs" as a name for some of their audiotape material. Modern dynamic geometry now allows a person to create changing images of geometrical objects, but most people can find a way of making pictures "in the head" and giving them some movement. This technique can be used with pupils and it can develop a number of benefits: comprehension, communication, construction--allowing ideas to be discussed and creativity to flourish. Here, the author suggests on watching Trevor's film so that teachers might consider how they could enable students to work creatively on the ideas contained in the film. (Contains 5 figures and 2 notes.)