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Zonish ball model

When I found George Hart's fascinating fork sculpture, I've wanted to reconstruct it. There is a longer description of the underlying desing, which says that it based on a so-called zonish polyhedron.

On the surface of the sculpture pentagons and triangles were formed; it was constructed from 240 forks. Each fork met four others: it went below the ones at the end, and above two other ones somewhere in the middle. Based on this observation, the new construction should have three-fold symmetry points at the vertices of a dodecahedron, and five-fold symmetry points at the midpoints of its faces. Trying several configurations those where midpoints of edges were centers of rhombs whose sides were perpendicular to two triangles and two pentagons seemed particularly appealing. You can see these points - projected to the circumscribed sphere - on the rotating picture. During the fine tuning, lengths and other parameters have been chosen so that the "necktie" along the rhomb's side should be approximately symmetrical. Based on this computer model, I've constructed the patterns. There are four kind of strips, 60 of each, coming in two different lengths. On each sheet you can find 30 strips, so you need two sheets of each. Once the strips have been cut, you can glue them together so that they overlap at the indicated positions.

The model was on display in one of CEU computer labs. The triangles are bicolor: yellow in the outside, and white in the inside.

[animated model] [zonish model]

 


Related external links:
 George Hart's web page
 No picnic by George Hart
 A paper on zonish polyhedra
   
Pattern sheets (pdf):
 Triangle sides
 Rhomb sides joining triangles
 Pentagon sides
 Rhomb sides joining pentagons
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