Exploring Noble Polyhedra With the Program Stella4D
Ulrich Mikloweit
The special thing about noble polyhedra is that they are both isogonal and isohedral. The most well-known are the five platonic solids, the four Kepler-Poinsot polyhedra and the two infinite sets of the disphenoids and the crown polyhedra. Already more than 120 years ago, isogonal-isohedral polyhedra were the subject of intensive research. At the turn of the 20th century, Max Brückner carried out a systematic search for them and published his results in 1906. The photos of his models give a good impression of the tremendous complexity and beauty of these bodies. Unfortunately, the models did not survive the two world wars, and with them the interest in them waned. So far there is no complete list of all noble polyhedra. Fortunately, today we have a very powerful tool that we can use to search for them more easily, namely the Stella4D program. The program has many cunning features with which you can create new polyhedra, e.g. Faceting. Here, the corners of a given polyhedron are connected by new edges, so that a new polyhedron is created. If you now select the isohedral option, you get a polyhedron that is set up by only one type of face. If you have taken as the starting polyhedron an isogonal one, there is a high probability that the new structure is noble. Many of these structures are compounds made from several dispenoids or crown polyhedra, as was the case with Brückner. In my research, I limited myself to distinct polyhedra. In addition to the nine mentioned above, I have found 52 other noble polyhedra, of which, to my knowledge, 19 have not yet been described. These are extremely attractive structures that manage to assemble bizarrely shaped faces into highly symmetrical bodies. Representing these as physical models is a major challenge and I hope to be able to build one or the other noble polyhedron over the next few years.
Additional information
Bridges Archive page for this paper
Discussion