Entropy alone can create complex crystals from simple shapes; tetrahedra packing record broken

In a study that elevates the role of entropy in creating order, research led by the University of Michigan shows that certain pyramid shapes can spontaneously organize into complex quasicrystals.A quasicrystal is a solid whose components exhibit long-range order, but without a single pattern or a unit cell that repeats.
A paper on the findings appears in the Dec. 10 issue of Nature. Researchers from Case Western Reserve University and Kent State University collaborated on the study.
Entropy is a measure of the number of ways the components of a system can be arranged. While often linked to disorder, entropy can also cause objects to order. The pyramid shape central to this research is the tetrahedron---a three-dimensional, four-faced, triangular polyhedron that turns up in nanotechnology and biology.[...]