Perfectly Round Zome Models

Every model here is perfectly round: all of its balls sit at exactly the same distance from the centre — equal in exact arithmetic, not merely to within a tolerance — so they lie on a common sphere. Every edge of the convex hull is a single standard strut. Drag to rotate any model. For shells that are very round but not exactly so, see Approximate Zome Spheres.

Truncated icosidodecahedron - 120 balls 180 struts — Truncated icosidodecahedron — 120 balls 180 struts An Archimedean solid. All 120 balls lie in one orbit, so a common radius comes free from the symmetry.

240 balls (variant a) 420 struts Two orbits at a common radius.

240 balls (variant b) 420 struts Two orbits at a common radius.

240 balls (variant c) 450 struts Three orbits at a common radius.

360 balls 600 struts Three orbits. Most balls with full icosahedral symmetry, struts of length 0-2.

480 balls 720 struts Four orbits. Most balls with full icosahedral symmetry, struts of length 0-3.

Physical construction

Scott Vorthmann and I built the 240-ball model, variant A, shown in the interactive gallery above. Its spherical shell has 240 balls and 420 struts. The red struts support the model and are not part of the sphere.

Two builders beside the completed blue-and-green 240-ball Zometool shell — The completed 240-ball model, built by Nan Ma and Scott Vorthmann.

The 240-ball Zometool shell on the floor, with blue and green struts and red support legs — A closer view of the shell.

The blue-and-green 240-ball Zometool shell suspended from the ceiling — The shell suspended from the ceiling.