Regular polyhedra

Regular polyhedra in nature

Regular polyhedra appear in biology as well. The coccolithophoreBraarudosphaera bigelowii has a regular dodecahedral structure, about 10 micrometres across. In the early 20th century, Ernst Haeckel described a number of species of radiolarians, some of whose shells are shaped like various regular polyhedra. Examples include Circoporus octahedrus, Circogonia icosahedra, Lithocubus geometricus and Circorrhegma dodecahedra; the shapes of these creatures are indicated by their names. The outer protein shells of many viruses form regular polyhedra. For example, HIV is enclosed in a regular icosahedron, as is the head of a typical myovirus.