57-cell
From Biocrawler, the free encyclopedia.
In mathematics, the 57-cell is a four-dimensional self-dual abstract regular polytope. Its facets are hemi-dodecahedron, and as its name implies, are 57 in number. It also has 57 vertices, 171 edges and 171 ridges. Its symmetry group is the projective special linear group L2(19), so it has 3420 symmetries. It has Schläfli symbol {5,3,5}. It was discovered by H. S. M. Coxeter in 1982.
