Molecular self-assembly—the organization of molecular components into ordered structures without external guidance—is a promising strategy for making complex materials that could be useful for nanotechnology or have biological applications. In 2012, researchers demonstrated that synthetic DNA strands called “DNA bricks” could self-assemble into complicated three-dimensional equilibrium structures, including letters of the English alphabet and shapes with well-defined cavities and tunnels [1]. The demonstration came as a great surprise to researchers in the field of DNA nanotechnology: the structures had formed from about 1000 different types of DNA brick, yet the general expectation was that large numbers of component types would be unable to assemble in an error-free way [2]. Now, inspired by those experiments, Aleks Reinhardt and Daan Frenkel at the University of Cambridge in the UK, reporting in Physical Review Letters[3], have used computer simulations to reproduce this result without accounting for the specific molecular details of DNA. In doing so, they have demonstrated that a wide range of distinct components—from molecules to fabricated nanoparticles—could self-assemble into precisely defined structures.