1 0 0 0 0 1 0 0 0 0 1 0
-1 0 0 0 -1 1 0 0 0 0 -1 1/2
1 0 0 0 0 1 0 0 0 0 -1 1/2
-1 0 0 0 -1 1 0 0 0 0 1 0