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