This set of ten discs will give a variety of interesting optical illusions when rotated in the flashing light of a stroboscope. When the flash rate per minute of the stroboscope equals the RPM of a spinning disc with a single printed image, the disc and its image will appear to be stationary.
When the disc has multiple printed images, there will be a number of ratios between the flash rate and the rotator RPM which will produce innumerable stationary or moving images. In this we can create the illusion of engine pistons moving up and down in a cylinder or of balls rolling around in a circle.
Each disc is approximately 20 cm in diameter and has a brass grommet in the center for mounting on the mandrel of a standard rotator (see WINSCO model ER-6A or ER-12A). The discs are printed on heavy cardboard stock for durability, some in two colors.