mtllib cube.mtl
o Cube
v  1.000000 -1.000000 -1.000000
v  1.000000 -1.000000  1.000000
v -1.000000 -1.000000  1.000000
v -1.000000 -1.000000 -1.000000
v  1.000000  1.000000 -1.000000
v  1.000000  1.000000  1.000000
v -1.000000  1.000000  1.000000
v -1.000000  1.000000 -1.000000
vn  0.000000 -1.000000  0.000000
vn  0.000000  1.000000  0.000000
vn  1.000000  0.000000  0.000000
vn  0.000000  0.000000  1.000000
vn -1.000000  0.000000  0.000000
vn  0.000000  0.000000 -1.000000

v -10 -1 -10
v  10 -1 -10
v  10 -1  10
v -10 -1  10
vn 0 1 0

usemtl Red
s off
f 2//3 6//3 5//3 1//3
f 4//5 8//5 7//5 3//5

usemtl Green
s off
f 4//1 3//1 2//1 1//1
f 6//2 7//2 8//2 5//2

usemtl Blue
s off
f 3//4 7//4 6//4 2//4
f 8//6 4//6 1//6 5//6

o Ground
usemtl Ground
s off
f 9//7 10//7 11//7 12//7