v 1 0 0
v 0 1 0
v 0 0 1
v -1 0 0
v 0 -1 0
v 0 0 -1
f 1 2 3
f 2 4 3
f 4 5 3
f 5 1 3
f 1 6 2
f 2 6 4
f 4 6 5
f 5 6 1