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