Figure 6.

Three shells grown with icosahedral symmetry, reminiscent of viral shells. These shells contain (A) 20, (G) 60, and (H) 80 subunits corresponding to T = 1, T = 3, and T = 4 viral shells based on the Caspar-Klug classification of icosahedral shells. Larger icosahedral shells are not seen in the simulated nonreversible growth model, perhaps explaining why scaffolding is needed for all larger icosahedral viruses. To see this figure in color, go online.