The Mutoscope was an early coin-operated arcade device that allowed people to watch 'moving pictures' (often peep shows) by essentially quickly flipping though a book of still images on stiff card stock. One person at a time could use the machine, which was marketed by the American Mutoscope Company starting in 1895. A subsequent firm, International Mutoscope Reel Company, made all manner of penny-arcade machines in the 1930s and '40s, including ones that dispensed 5.25-by-3.25-inch cheesecake cards of young women in various states of undress. There are almost 300 different types of these cards—those in the Yankee Doodle Girls series are considered rare.