(VAR x)
(RULES
  f(x,x) -> g
  a -> b
  a -> c
  b -> b
  c -> c
  f(a,x) -> g
  f(b,x) -> g
  f(c,x) -> g
  f(x,a) -> g
  f(x,b) -> g
  f(x,c) -> g
)
(COMMENT Example showing that signature extension and currying do not preserve NF, from [KKSdV96])