A little frustration can make life interesting. This is certainly the case in physics, where the presence of competing forces that cannot be satisfied at the same time – known as frustration – can lead to rare material properties. Just as water molecules become more ordered when they cool and freeze into ice crystals, the atoms of magnets become more ordered with decreasing temperature as the tiny magnetic fields or ‘spins’ of individual atoms start to point in the same direction. So-called ‘spin liquids’ are the exception to this rule, with spins continuing to fluctuate and point in different directions even at very low temperatures.