{ x27 = piecewise(0, t < -1, piecewise(0, t < 0, 10)),
  x28 = piecewise(0, t < -1, piecewise(0, t < 0, 10)),
  x29 = k27*x2,
  x30 = k28*x6,
  x31 = k29*x8,
  x32 = k30*x10,
  x33 = k31*x12,
  x34 = k32*x24,
  x35 = k33*x14,
  x36 = k34*x16,
  x37 = k35*x18,
  x38 = k36*x20,
  x39 = k37*x22,
  1*k38*x1 + 1*k38*x2 + 1*k38*x3 = k38*k39,
  1*k38*x4 + 1*k38*x5 + 1*k38*x6 = k38*k40,
  1*k38*x7 + 1*k38*x8 = k38*k41,
  1*k38*x9 + 1*k38*x10 = k38*k42,
  1*k38*x11 + 1*k38*x12 = k38*k43,
  1*k38*x13 + 1*k38*x14 = k38*k44,
  1*k38*x15 + 1*k38*x16 = k38*k45,
  1*k38*x17 + 1*k38*x18 = k38*k46,
  1*k38*x19 + 1*k38*x20 = k38*k47,
  1*k38*x21 + 1*k38*x22 = k38*k48,
  1*k38*x23 + 1*k38*x24 = k38*k49,
  1*k38*x25 + 1*k38*x26 = k38*k50 }