Normal crystals, likes diamond, are an atomic lattice that repeats in space, but physicists recently suggested making materials that repeat in time. Last year, reseachers sketched out the phases surrounding a time crystal and what to measure in order to confirm that this new material is actually a stable phase of matter. This stimulated two teams to build a time crystal, the first examples of a non-equilibrium form of matter. -sciencedaily article on time crystals
It needs further confirmation, but time crystals might indeed be possible. Some recent articles had suggested they might be impossible, but this new research suggests they may actually be possible. Further information in favor or against is needed.