Subdivision of a rectangular Bezier surface
Subdivision of a triangular Bezier surface
Subdivision of a rectangular Bezier surface
The de Castlejau algorithm can be used to subdivide a Bezier surface
into Bezier spline patches.
Remark: The Bezier nets associated with repeated subdivision converge
to the Bezier surface. The Bezier net approximates the surface, and
can be used to compute intersection curves of Bezier surfaces. The figure
shows the approximation of a Bezier surface by repeated refining of
the Bezier net.
Subdivision of a triangular Bezier surface 
