{{1, 0, 0, 0, -1, 0, 0, 0, 0}, {0, 1, 0, 0, -1, 0, 0, 0, 0}, 
 {0, 0, 1, 0, 0, -2, 0, 0, -1}, {0, 0, 0, 1, 0, -2, -2, -1, 0}}
