Math Monday: Morton Bradley sculpture

Education Science
Math Monday: Morton Bradley sculpture

Morton Bradley sculpture

By George Hart for the Museum of Mathematics

It’s amazing what can be made from paper. These two mathematical sculptures by Morton C. Bradley are 16″ and 20″ in diameter, respectively, made from 2-ply Strathmore paper. The geometric forms are each based on twelve copies of a Kepler-Poinsot polyhedron, with twelve great dodecahedra on the left and twelve small stellated dodecahedra on the right. If you want to try putting together your own paper models, all you really need to know is that, in each case, the visible facets are isosceles triangles in which the ratio of one edge length to the other is 1.618. In the form below-left, each triangle has two equal short edges and one longer edge; at right, they have two equal longer edges and one short edge.


The originals, now at the Indiana University Art Museum, took months to painstakingly create and paint in the 1970s, but modern additive fabrication techniques can make plastic replicas of the forms in hours (see below). These three-inch models were made from nylon by selective laser sintering. If you have access to a 3D printing machine, you can make your own copies of these and other Bradley designs by downloading the STL files available here. At The Museum of Mathematics, we like the way these illustrate both the beauty of math and the notion that complex structures can be understood in terms of simpler parts.


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Introducing “Math Monday”

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Gareth Branwyn is a freelance writer and the former Editorial Director of Maker Media. He is the author or editor of over a dozen books on technology, DIY, and geek culture. He is currently a contributor to Boing Boing, Wink Books, and Wink Fun. His free weekly-ish maker tips newsletter can be found at

View more articles by Gareth Branwyn


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