A chromatrope is a type of magic lantern slide that produces dazzling, colorful geometrical patterns set in motion by rotating two painted glass discs in opposite directions, originally with a double pulley mechanism but later usually with a rackwork mechanism. These 3 on auction are used , 1 has a rotating glass ring with different heads , some damage to the heads and rotating is difficult. 1 is loose in the frame . See all pictures as they are part of the description.