Function Follows Form

Abstract

Cover: the front cover shows four densest packings of rounded tetrahedra, from left to right the dimer crystal, a quasicrystal approximant, a crystal similar to β-tin, and a deformed face-centered cubic crystal. The back cover shows rounded tetrahedral particles self-assembled within a slowly shrinking spherical shell. During this process, particles pack together to fill space as efficiently as possible, which leads to a complicated structure with hexagonal cells that is revealed by coloring particles according to their orientation. The background image of both the front and back is a snapshot of a simulation of self-propelled rods.