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