Seems good to me. I just suggest to change sides triangulation to
as it provides better smoothing.
Code:
4 16 10 0 -.5 10 8 -20 10 8 20 10 0 20
4 16 10 4 -20 10 0 -.5 10 -14 -.5 10 -14 -2.45
3 16 10 4 -20 10 8 -20 10 0 -.5