The Thaumatrope.

A Thaumatrope is an optical illusion. It is done through a piece of paper, cut in the shape of a circle, and two pieces of string attached at each end, finally on the paper, draw an image on each side. If you then spin those strings, you will see the images fusing crating a piece of animation.

A disadvantage of the thaumatrope is it gets old very quickly. However, the advantage through this is that it's an opportunity to make more and challenge yourself to see what neat little animations you can make.

This was invented by both Peter Mark Roget or John Ayrton Paris, in London during the year 1824, Paris showed The Royal College of Physicians one of these to explain the persistence of vision.

John Cutter, played by Michael Caine, uses a thaumatrope to explain the persistence of vision, in the film "The Prestige". Also, there is a thaumatrope used in the film "Sleepy Hollow" by Ichabod Crane, played by Johnny Depp.

Though the Thaumatrope consisting of strings, being pulled to rotate paper, is the most popular form of it, there is another version. In this version, you place the paper image faced down, then glue a stick on top of that paper, then glue the other paper image facing upwards on top of that. Now place the stick between your hands and through rubbing your hands back an fourth, see your images fuse.

Examples:-