a, Ferroelectric materials consist of domains that are electrically polarized in different directions (arrows) and separated by domain walls. b, When an electric field is applied to a ferroelectric material, domains polarized in the direction of the field grow at the expense of others (P, polarization). The square 'nucleus' represents the initial growth of the red domain into the blue domain. c, Liu et al.3 report a theoretical description of domain-wall motion that depends on the potential-energy variation associated with the crystal lattices of ferroelectric materials. The method starts by calculating the structure and energetics of a few hundred atoms at the atomic scale and quantum level, then progressively 'zooms out' to a larger scale (up to 850,000 atoms; not shown), before finally deriving an analytical description of the bulk material that internalizes key parameters derived in the first two steps, but does not explicitly consider the microscopic details.