1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
xy1 xy2 yx3 xy4 xy5 yx6 xz11 xz12 zx13 xz14 xz15 zx16 -10 -9 -8 -7 -6 -5 0 -9