MainStir your morning tea or coffee and watch. To explain the formation of a vortex in your hot beverage, physicists, engineers and mathematicians treat fluids as continua and ignore the complex dynamics at the molecular scales: they use the basic laws of fluid mechanics. Beyond fluids, descriptions of living matter as continua have been instrumental in understanding the large-scale flows of the cytoskeleton, cell tissues and animal groups, where the interactions between the elementary units rem...