In laboratories where matter is observed at its most intimate scale, researchers have discovered that a liquid need not demand the restlessness of every atom it contains. Christopher Leist and colleagues, working with platinum nanoparticles on graphene, found that individual atoms could be pinned motionless at lattice defects while the surrounding metal flowed freely — and that when enough of these still atoms formed a ring around a droplet's edge, they raised a mechanical wall against crystallization, holding the metal in a supercooled or amorphous state far below the temperature where order