v -1 -1 -1 0 0 0
v -1 -1 1  1 0 0
v -1 1 -1  0 1 0
v -1 1 1   1 1 0
v 1 -1 -1  0 0 1
v 1 -1 1   1 0 1
v 1 1 -1   0 1 1
v 1 1 1    1 1 1

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