A volvelle or wheel chart is a type of slide chart, a paper construction with rotating parts. It is considered an early example of a paper analog computer. Volvelles have been produced to accommodate organization and calculation in many diverse subjects. Early examples of volvelles are found in the pages of astronomy books.
A moveable device for working out the position of the sun and moon in the zodiac is known as a volvella.
In the twentieth century, the volvelle had many diverse uses. In Reinventing the Wheel, author Jessica Helfand introduces twentieth-century volvelles with this:
The rock band Led Zeppelin employed a volvelle in the sleeve design for the album Led Zeppelin III (1970).
Two games from the game company Infocom included volvelles inside their package as "feelies": Sorcerer (1983) and A Mind Forever Voyaging (1985). Both volvelles served to impede copying of the games, because they contained information needed to play the game. Other games included similar code wheels.