v 7 0.0 0.0
v 0 1.0 2.0
v 4 1.0 2.0
v 1 0.8 3.5
v 2 0.5 1.0
v 6 5.0 2.0
v 3 1.3 2.0
v 5 0.75 3.5
trivid tri1 0 2 1
trivid tri3 5 7 6
trivid tri2 3 5 4