photodrome
Pho"to*drome, n. Etym: [Photo- + Gr. (Physics) Defn: An apparatus consisting of a large wheel with spokes, which when turning very rapidly is illuminated by momentary flashes of light passing through slits in a rotating disk. By properly timing the succession of flashes the wheel is made to appear to be motionless, or to rotate more or less slowly in either direction.