lx (left end-point, x-coordinate)
1,  0 -1
2,  0 0 1
-1,
-1,
2,  0 -1 1
1,  0 -1
-1,
-1,
-1,
3,  0 0 -1 3
2,  0 0 -1
-1,
1,  0 -1
ly (left end-point, y-coordinate)
-1, 
3,  0 1 0 -1
6,  0 0 0 0 1 0 1
6,  0 0 0 0 1 0 -1
-1,
6,  0 0 0 0 0 0 2
6,  0 0 0 0 0 0 1
1,  0 1
1,  0 1
6,  0 0 0 0 0 0 3
6,  0 0 0 0 0 0 1
4,  0 0 0 0 1
-1,
rx (right end-point, x-coordinate)
1,  1 -2
2,  1 0 -1
0,  1 
1,  1 -2  
2,  1 0 -2
1,  1 -1
0,  1
3,  1 0 0 1
2,  1 0 -2
1,  1 -2
2,  1 0 -2
0,  1
1,  1 1
ry (right end-point, y-coordinate)
6,  0 0 2 0 0 0 2
3,  0 0 0 1
4,  0 0 0 1 3
6,  0 0 2 0 0 0 -1
4,  0 0 0 2 -2
6,  0 0 0 0 0 0 2
4,  0 0 0 1 2
-1,
4,  0 0 0 2 -1
6,  0 0 2 0 0 0 1
4,  0 0 0 2 -3
-1,
-1,