Problem:
 from(X) -> cons(X,from(s(X)))
 2ndspos(0(),Z) -> rnil()
 2ndspos(s(N),cons(X,Z)) -> 2ndspos(s(N),cons2(X,Z))
 2ndspos(s(N),cons2(X,cons(Y,Z))) -> rcons(posrecip(Y),2ndsneg(N,Z))
 2ndsneg(0(),Z) -> rnil()
 2ndsneg(s(N),cons(X,Z)) -> 2ndsneg(s(N),cons2(X,Z))
 2ndsneg(s(N),cons2(X,cons(Y,Z))) -> rcons(negrecip(Y),2ndspos(N,Z))
 pi(X) -> 2ndspos(X,from(0()))
 plus(0(),Y) -> Y
 plus(s(X),Y) -> s(plus(X,Y))
 times(0(),Y) -> 0()
 times(s(X),Y) -> plus(Y,times(X,Y))
 square(X) -> times(X,X)

Proof:
 Containment Processor: loop length: 1
                        terms:
                         from(X)
                        context: cons(X,[])
                        substitution:
                         X -> s(X)
  Qed