(VAR X Y Z )
(RULES 
        sel(0, cons) -> X
        sel(s, cons) -> sel(X, Z)
        dbl1(s) -> s1(s1(dbl1(X)))
        sel1(0, cons) -> X
        sel1(s, cons) -> sel1(X, Z)
        quote(s) -> s1(quote(X))
        dbl(0) -> 0
        dbl(s) -> s
        dbls(nil) -> nil
        dbls(cons) -> cons
        indx(nil) -> nil
        indx(cons) -> cons
        from -> cons
        dbl1(0) -> 01
        quote(0) -> 01
        quote(dbl(X)) -> dbl1(X)
        quote(sel(X, Y)) -> sel1(X, Y)
        
)