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