There is something universally appealing about the slap bracelet, and the way a simple tap causes it to switch between a straight shape and a curled one. What you probably didn’t know is that a slap bracelet’s satisfying snap is the same principle behind bistable structures. These can toggle between two stable positions (one representing 0 and the other 1) to store data directly within their physical forms as mechanical bits (m-bits).

Because of their exciting potential for efficient control of robotic and other mechanical systems, researchers have been engineering special materials with programmable structures (programmable metamaterials) for years. But until now, actual programming of such systems has been a major challenge: mechanical bits must typically be controlled individually, which is extremely cumbersome and time-consuming.

Now, researchers in the Flexible Structures Laboratory (fleXLab) in EPFL’s School of Engineering, the Dutch research institute AMOLF, and Leiden University have found a way to program metamaterials globally with a surprisingly simple solution: rotation. By tuning a spinning platform’s speed, direction, and acceleration, the researchers can harness forces arising in a rotating system—such as centrifugal and Euler forces—to make elastic beams snap back and forth, creating a simple new way to “write” multiple mechanical bits at once.