parent(tom, bob).
parent(tom, liz).
parent(bob, ann).
parent(bob, pat).
parent(pat, jim).

grandparent(X, Z) :- parent(X, Y), parent(Y, Z).
ancestor(X, Y) :- parent(X, Y).
ancestor(X, Y) :- parent(X, Z), ancestor(Z, Y).

:- initialization(main).

main :-
    write('Grandparents of jim: '),
    findall(X, grandparent(X, jim), Grandparents),
    write(Grandparents), nl,
    write('Ancestors of jim: '),
    findall(X, ancestor(X, jim), Ancestors),
    write(Ancestors), nl.