v 0 0 0
v 1 0 0
v 0 1 0
v 1 1 0
v 0 0 1
v 1 0 1
v 0 1 1
v 1 1 1
f 1 2 6
f 1 3 2
f 1 5 3
f 1 6 5
f 2 3 4
f 2 4 8
f 2 8 6
f 3 5 7
f 3 7 4
f 4 7 8
f 5 6 8
f 5 8 7