{{1, 0, 0, 0, -1, 0, 1, 1/2, -1, -1/2, -1, 1/2, -1/2}, 
 {0, 1, 0, 0, 0, 0, -1, -1/2, 1, 1/2, 0, -1/2, 1/2}, 
 {0, 0, 1, 0, -2, -2, 6, 3, -6, -4, -2, 3, -4}, 
 {0, 0, 0, 1, 0, -2, 2, 1, -2, -2, 0, 1, -2}}
