Scientists seeking to understand the intricacies of high-temperature superconductivity — the ability of certain materials to carry electrical current with no energy loss — have been particularly puzzled by a mysterious phase that emerges as charge carriers are added that appears to compete with superconductivity. It’s also been a mystery why, within this “pseudogap” phase, the movement of superconducting electrons appears to be restricted to certain directions. Detailed studies of a material as it transforms from an insulator through the “pseudogap” into a full-blown superconductor links two “personality” changes of electrons at a critical point.