VOLVELLES

The word Volvelle comes from the Latin verb volvere, which means to turn. For more than 800 years, designers and paper engineers have included volvelles within books to educate and entertain readers. The moving parts of a volvelle can often be the best way to illustrate complicated subjects, from the vast expansion of the planets to the compact arrangement of organs in the human body.  [To see more volvelles, take a look at Cosmographicus, found in the Smithsonian Libraries.]

Here’s how it works: Layered circles of parchment are held together at the center by a tie, allowing the user to rotate the circles. When using a volvelle to crack a cypher, a key is used to help the user locate the alignment of the smaller circle to the larger circle. Once aligned, the code reveals its corresponding letters.