[ Diff(x[1], t) = ((-1)*k[10]*k[3]*x[1] + 1*k[10]*(k[2] - k[1]*x[3])*(1 - piecewise(x[3] - k[2]/k[1] > 0, 1, 0)))/k[10],
  Diff(x[2], t) = (1*k[10]*k[4]*x[1] + (-1)*k[10]*k[5]*x[2])/k[10],
  Diff(x[3], t) = (1*k[10]*k[6]*x[2] + (-1)*k[10]*k[7]*x[3])/k[10] ]