There was a recent article about the creation of 4D spacetime crystals based on recent theory proposed by Frank Wilczek. This theory is based on breaking time translational symmetry which basically is the assumption that the laws of physics are time invariant (e.g. that we can expect our physical laws are the same as we move through time).
The concept of spactime crystals is relatively new, and there are classical and quantum versions. Since the time crystal reportedly returns to its ground state periodically, and it reportedly is not in violation of the second law of thermodynamics, the layman might be tempted to look at it as a some sort of pulsating refrigerator.
Is there some better description of the time crystal that makes it obvious that this is really a new concept?