Yo-yos date back more than 2,000 years to China and Greece. They rolled their way into Europe, and by the 18th century the "¿migrette" or "quiz" had become a favored toy of aristocrats.
All along, the string was tied to the axle, causing the spinning disks to return up the cord immediately after they hit bottom. But aficionados in the Philippines looped a string around the axle, so the wooden disks could spin freely, or sleep, while hanging down. This innovation made possible numerous tricks with names such as cat's cradle and walk the dog. Filipino Pedro Flores immigrated to the U.S., started manufacturing yo-yos in 1928, and began the first American craze for this toy. Cheap and durable, it was one of the few commercial successes of the Great Depression.
This article was originally published with the title String Theory.