v -1.0 -1.0 -1.0 v -1.0 1.0 -1.0 v 1.0 1.0 -1.0 v 1.0 -1.0 -1.0 v 1.0 -1.0 1.0 v 1.0 1.0 1.0 v -1.0 1.0 1.0 v -1.0 -1.0 1.0 f 1 2 3 f 3 4 1 f 5 6 7 f 7 8 5 f 1 8 2 f 7 2 8 f 3 6 4 f 5 4 6 f 2 7 3 f 6 3 7 f 4 5 1 f 8 1 5