Scientists have developed a material that can grow and coordinate its own movement until the entire structure pulses in unison, paving the way for versatile robots that behave more like living systems.

Publishing their findings today (Oct. 14) in Nature, engineers from the University of Birmingham working with the universities of Amsterdam, Lyon, Delft, Leiden and Cambridge reveal that they have created a mechatronic metamaterial that behaves as a ‘time crystal.’ Time crystals are an unusual form of matter in which particles endlessly move in regular, repeating cycles. But here, the “particles” were not the atoms of molecules: they were robots.

The scientists’ experimental material combines elastic structures, sensors, electronics and actuators so that neighboring components can influence one another. The key ingredient to generate the time-crystalline state was making the interactions between components “nonreciprocal,” meaning that one component’s response to another does not have to be mirrored in reverse.