Demonstrates both longitudinal and transverse wave motion simultaneously. A number of circular discs are mounted equidistantly on a central shaft with gradually varying degrees of eccentricity. The shaft is mounted on a metal frame, and capable of rotating about the horizontal axis through the handle. A number of metal rods are supported on the top of the discs, with 2/3rd straight, and 1/3rd rods bent in an L-shape, with their other ends sliding into a metal guide. On rotating the discs, the straight rods depict transverse wave motion, while the bent rods show longitudinal wave motion.