Time Crystals?

https://en.wikipedia.org/wiki/Time_crystal

A time crystal or space-time crystal is an open system in non-equilibrium with its environment that exhibits time translation symmetry breaking (TTSB). It is impossible for a time crystal to be in equilibrium with its environment. The idea of a time crystal was first put forward by Nobel laureate and MIT professor Frank Wilczek in 2012.^[a] Space-time crystals extend the ordinary three-dimensional symmetry seen in crystals to include the fourth dimension of time; a time crystal spontaneously breaks the symmetry of time translation. The crystal's pattern repeats not in space, but in time, which allows for the crystal to be in perpetual motion.^[2] Time crystals are closely related to the concepts of zero-point energy and the dynamical Casimir effect.^[b]