(VAR X Y)
(STRATEGY CONTEXTSENSITIVE 
  (nats)
  (adx 1)
  (zeros)
  (cons)
  (0)
  (incr 1)
  (s)
  (hd 1)
  (tl 1)
)
(RULES 
nats -> adx(zeros)
zeros -> cons(0,zeros)
incr(cons(X,Y)) -> cons(s(X),incr(Y))
adx(cons(X,Y)) -> incr(cons(X,adx(Y)))
hd(cons(X,Y)) -> X
tl(cons(X,Y)) -> Y
)