Schläfli symbol

In geometry, the Schläfli symbol is a notation of the form {p,q,r, ...} that defines regular polytopes and tessellations.

The Schläfli symbol is named after the 19th-century Swiss mathematician Ludwig Schläfli, who generalized Euclidean geometry to more than three dimensions and discovered all their convex regular polytopes, including the six that occur in four dimensions.