Coba jelasin Facet, sebuah (n-1) dari Daftar bentuk matematika dong

Ridge, sebuah elemen dimensi (n-2)

Peak, sebuah elemen dimensi (n-3)

For example, in a polyhedron (3-dimensional polytope), a face is a facet, an edge is a ridge, and a vertex is a peak.

Vertex figure: not itself an element of a polytope, but a diagram showing how the elements meet.