(VAR X Y Z)
(STRATEGY CONTEXTSENSITIVE 
  (f 1)
  (cons 1)
  (g 1)
  (0)
  (s 1)
  (sel 1 2)
)
(RULES 
f(X) -> cons(X,f(g(X)))
g(0) -> s(0)
g(s(X)) -> s(s(g(X)))
sel(0,cons(X,Y)) -> X
sel(s(X),cons(Y,Z)) -> sel(X,Z)
)