Here's how to make one
This is a very simple toy to build. Cut out a round disc from a piece of fairly thick white paper board (illustration board). Make the circle anywhere from 2 to 10 inches across. Punch two holes at opposite sides, placing them as nearly exactly opposite as possible. Tie a loop of string through each pair of holes. The loops should be short enough so that you can easily hold the device while it is stretched out. If you want to replicate the original image, draw a bird on one side of the disc, and a cage on the other. The bird should be centered so that it will fit in the cage when the disc is flipped. Hold the string ends one in each hand and "wind" the Thaumatrope by flipping the disc, which will cause the string to twist. Once the loops are twisted, gently pull them apart, and the disc should spin, putting the bird in the cage.
