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 4
f 5 6 7 8
l 1 5
l 2 6
l 3 7
l 4 8