Triangular Bezier Patch Format

This is an s3d like syntax for a triangular Bezier patch.  As with s3d,
lines starting with '#' are comments.

A triangular Bezier patch begins with the line 'B dim deg f', where
dim should be filled in with the dimension of the domain and deg
should be filled in with the degree of the patch.  For surfaces,
the dimension will always be two.  'f' is a flag that is 0 if the
domain is explicitly stated, and 1 if it isn't.

Next follows two lists of vertices (or only one list if the 'f' flag
is 1).  The first list gives the simplicial domain, while the second
list gives the range.  The domain list of vertices is omitted if the
'f' flag is 1.  The assumed domain when the 'f' flag is given is
the origin and the dim unit points.  Example, for dimension 2, the
assumed domain is {(0,0), (1,0), (0,1)}.  Note that for many operations
(such as tesselating the surface), the domain is irrelvant.

Note that the domain vertices should have as many coordinates as
specified by the dimension given in the B command.  The range vertices
can have an arbitrary number of coordinates, but must all have the
same number.  For surfaces, the range points will typically have 3
coordinates.

The range vertices are ordering by increasing multiindex.  E.g, for
dimension 2 and degree 3, the vertices are order as
	003 012 021 030 

Example:

B 2 2 0
# domain
v 0 0
v 0 1
v 1 1
# range
v 0 0 0
v 0 0 1
v 0 1 0
v 0 0 2
v 1 1 1
v 0 2 0
E 0 0 0