Mutual Support

George W. Hart

This seven-inch diameter steel sculpture is made of twenty identical parts, cut with a computer-controlled plasma cutter. They are assembled to interlock with icosahedral symmetry, and I had the result powder coated carmine red. The assembly was quite difficult, taking me several days, because it all wants to fall apart until the last piece is in place to lock everything together. No welding, brazing or other "glue" holds the pieces together, just the springiness of the steel. The assembly's coherence relies on the mutual support of the parts. It is a refinement of a puzzle design I had made in plastic several years ago, but now I could use thinner parts as the material is steel.

Above is a computer rendering I made while designing the sculpture.

This view looks down a five-fold axis, the same as the computer image above it.

Above is an image of the actual part design. It is a simple three-armed "windmill".

Above is another view, looking down a three-fold axis, orthogonal to the plane of one part.
This sculpture was part of the art exhibit at the 2007 AMS/MAA joint math meeting in New Orleans.

Thank you Tony Vigliotti for providing the powder coating.