The Mesoamericans were robust users of rubber, according to historical and archaeological records. With it they made sandals, rubber bands and also balls, which they used to play a ceremonial game in stone-walled courts.

Each of these items need different qualities in the rubber of which they are made. A ball requires elasticity for bounciness, a rubber band requires strength, and a sandal requires wear and resistance.

A new study reports that the Mesoamericans, which include the Aztec and the Maya, knew how to make different kinds of rubber, mixing latex from rubber trees with juice squeezed from morning glory vines in different proportions.

“It’s a pretty safe bet that they were engineering materials to suit their needs,” said Michael Tarkanian, the study’s lead researcher and a materials scientist at M.I.T. “It wasn’t just a haphazard concoction.”