@pimms.value<EOL><INDENT>def face_neighbors(edge_faces, face_count):<DEDENT>
q = [[] for _ in range(face_count)]<EOL>for fs in edge_faces:<EOL><INDENT>if len(fs) == <NUM_LIT:2>:<EOL><INDENT>(a,b) = fs<EOL>q[a].append(b)<EOL>q[b].append(a)<EOL><DEDENT><DEDENT>return tuple([tuple(qq) for qq in q])<EOL>
tess.face_neighbors is a tuple that contains one element per face; each element
tess.face_neighbors[i] is a tuple of the 0-3 face indices of the faces that are adjacent to
the face with index i.