# test_file
v -18.500000 -24.500000 31.000000
v -18.500000 -24.500000 -0.001000
v 12.500000 -24.500000 -0.001000
v 12.500000 -24.500000 31.000000
v -18.500000 6.500000 31.000000
v -18.500000 6.500000 -0.001000
v 12.500000 6.500000 31.000000
v 12.500000 6.500000 -0.001000
vn 0.000000 -1.000000 0.000000,
vn 0.000000 -1.000000 0.000000,
vn -1.000000 0.000000 0.000000,
vn -1.000000 0.000000 0.000000,
vn 0.000000 1.000000 0.000000,
vn 0.000000 1.000000 0.000000,
vn 1.000000 0.000000 0.000000,
vn 1.000000 0.000000 0.000000,
vn 0.000000 0.000000 -1.000000,
vn 0.000000 0.000000 -1.000000,
vn 0.000000 0.000000 1.000000,
vn 0.000000 0.000000 1.000000,
f 1//1 2//1 3//1
f 1//4 3//4 4//4
f 5//7 6//7 2//7
f 5//10 2//10 1//10
f 6//13 5//13 7//13
f 6//16 7//16 8//16
f 7//19 4//19 3//19
f 7//22 3//22 8//22
f 8//25 3//25 2//25
f 8//28 2//28 6//28
f 5//31 1//31 4//31
f 5//34 4//34 7//34