(from AG01 3.42)
(VAR x)
(RULES
half(0) -> 0
half(s(0)) -> 0
half(s(s(x))) -> s(half(x))
lastbit(0) -> 0
lastbit(s(0)) -> s(0)
lastbit(s(s(x))) -> lastbit(x)
conv(0) -> cons(nil,0)
conv(s(x)) -> cons(conv(half(s(x))),lastbit(s(x)))
)