The outcrop of beds at the surface is commonly the truncation of these curves.
(By the truncation of a vertex or edge we mean the cutting away of the vertex or edge by a plane making equal angles with all the faces composing the vertex or with the two faces forming the edge.) It is bounded by 4 triangular and 4 hexagonal faces; there are 18 edges, and 12 vertices, at each of which two hexagons and one triangle are covertical.
Use of truncation toward zero in implicit conversion has not always been guaranteed in C either, by the way.
The -U (uniqueness) option is now misnamed as it actually controls truncation (as of version 0.80 ).
The truncation symbol $ finds all the words from a single stem.