[ Eq(1*x1 + 1*x2, k60),
  Eq(1*x9 + 1*x10, k61),
  Eq(1*x11 + 1*x12, k62),
  Eq(1*x13 + 1*x14, k63),
  Eq(1*x15 + 1*x16 + 1*x17 + 1*x18 + 1*x19 + 1*x20 + 1*x21 + 1*x22 + 1*x23, k64 + k65) ]