5 0.5

3 1 3 4
  -1 -1 -0.5

3 0 2 4
  1 -1 -0.5

3 1 3 4
  1 1 -0.5

3 0 2 4
  -1 1 -0.5

4 0 1 2 3
  0 0 0.5