Graphene is a single-atom thick plane of carbon atoms, arranged in a hexagonal pattern, and has some extraordinary properties, including very high electrical conductivity. Researchers at the University of California, Riverside, have accidently discovered an unpredicted property of stacked sheets of graphene. When stacking three layers on top of each, so the top and bottom layer line up, the material is a conductor, as expected, but if the top layer is shifted by one atomic width, the material becomes an insulator. This is an example of experiment getting ahead of theory as the researchers do not know what electronic interaction may be going on to cause this effect. Once it is better understood, the insulating form of graphene may be useful in future electronics, as single-layer graphene does not have a band gap, a property central to transistors.