diff(L,V) = (
  L = V → C1,
  car(L) = 0 → C0,
  car(L) = plus → cons(plus,maplist(cdr(L),λ(J,diff(car(J),V)))),
  car(L) = times →
           cons(plus,maplist(cdr(L),
                             λ(J,cons(times,maplist(cdr(L),
                                                    λ(K,(J≠K → copy(car(K)),
                                                         1 → diff(car(K),V))))))))
  1 → error)

maplist(L,f) = (L = 0 → 0
                1 → cons(f(L), maplist(cdr(L),f)))