[ [ 1,-1,0, 0,0, 0,0,0,0, 0 ],
  [ 0, 0,1,-1,0, 0,0,0,0, 0 ],
  [ 0, 0,0, 0,1,-1,0,0,0, 0 ],
  [ 0, 0,0, 0,0, 0,1,0,0, 0 ],
  [ 0, 0,0, 0,0, 0,0,1,0, 0 ],
  [ 0, 0,0, 0,0, 0,0,0,1,-1 ] ]