[ Diff(x[1], t) = (1*k[19]*k[1]*x[1]*(1 - x[1]/k[2]) + (-1)*k[19]*k[3]*x[1]*x[2] + (-1)*k[19]*k[9]*x[1]*x[3]/(k[11] + x[3]))/k[19],
  Diff(x[2], t) = (1*k[19]*k[5] + (-1)*k[19]*k[6]*x[2] + 1*k[19]*k[7]*x[1]*x[2]/(k[8] + x[1]) + (-1)*k[19]*k[4]*x[1]*x[2] + (-1)*k[19]*k[10]*x[2]*x[3]/(k[12] + x[3]) + 1*k[19]*k[14])/k[19],
  Diff(x[3], t) = ((-1)*k[19]*k[13]*x[3] + 1*k[19]*piecewise(t <= 1/8, k[17]/(1/8), piecewise(And(t >= 21, t <= 21 + 1/8), k[17]/(1/8), piecewise(And(t >= 42, t <= 42 + 1/8), k[17]/(1/8), piecewise(And(t >= 63, t <= 63 + 1/8), k[17]/(1/8), piecewise(And(t >= 84, t <= 84 + 1/8), k[17]/(1/8), piecewise(And(t >= 105, t <= 105 + 1/8), k[17]/(1/8), piecewise(And(t >= 126, t <= 126 + 1/8), k[17]/(1/8), 0))))))))/k[19] ]