x1[] x2[] N[]    y[]
   1    3  4.323 25
  -1    3  6.291 34
   1    5  0.893  6
  -1    5  1.092  4
   1    7  6.710 48
  -1    7 11.992 54
   1   10  5.773 30
  -1   10  7.521 28
   1   15  4.622 18
  -1   15  9.101 32
END