v  0.0  1.0  1.0
v  0.0  2.0  2.0
v  1.0  3.0  4.0
v  2.0  3.0  5.0
v  3.0  2.0  5.0
v  3.0  1.0  4.0
v  2.0  0.0  2.0
v  1.0  0.0  1.0

f 1 2 3 4 5 6 7 8