An anchor can be referred to in one of two ways; as a directional vector, or as a named anchor string ... These constants define unit vectors for the six axis directions as shown below. Figure 1.4.1: ...

A Bezier patch is a (N+1) by (M+1) grid of control points, which defines surface with four edges (in the non-degenerate case). Bezier Surface A surface defined by a list of one or more bezier patches.