v 0 50 0
v 100 30 0
v 0 1 100
v 100 100 100

vt 0 0
vt 20 0
vt 0 20
vt 20 20

vn 0.61 3.67 -0.78
vn 0.99 2.89 -0.13
vn 0.14 7.02 -0.98
vn 0.5 7.3 -0.86

s off
f 1/1/1 3/3/3 2/2/2
f 2/2/2 3/3/3 4/4/4