num_splines 1 bspline num_vertices 13 0 2 0 0 0 0 -2 0 0 -2 2 0 -2 4 0 2 4 0 2 2 0 3 2 0 3 -2 0 2 -2 0 -4 -2 0 -4 -1 0 2 -1 0