v 0 0 0 #1
v 0 1 0 #2
v 1 1 1 #3
v 1 0 1 #4
v 1 0 0 #5
v 1 1 0 #6
v 0 1 1 #7
v 0 0 1 #8
vt 0 1 #1
vt 0 0 #2
vt 1 0 #3
vt 1 1 #4
f 1/1 3/3 2/2 
f 1/1 4/4 3/3
f 1/1 2/2 3/3
f 1/1 3/3 4/4
f 5/1 7/3 6/2 
f 5/1 8/4 7/3
f 5/1 6/2 7/3
f 5/1 7/3 8/4