{ 1*k1*x1 + 1*k1*x2 + 1*k1*x3 + 1*k1*x5 = k1*k26,
  1*k1*x4 + 1*k1*x5 + 1*k1*x6 + 1*k1*x8 = k1*k27,
  1*k1*x7 + 1*k1*x8 + 1*k1*x9 + 1*k1*x11 = k1*k28,
  1*k1*x10 + 1*k1*x11 + 1*k1*x12 + 1*k1*x13 = k1*k29 }