%%does work

accDot([],[],A,A).

accDot([H1|T1], [H2|T2], A, Result) :-
  is(Anew,+(A,*(H1,H2))),
  accDot(T1, T2, Anew, Result).

dot(Vector1, Vector2, Result) :-
  accDot(Vector1, Vector2, 0, Result).



%% doesn't work

 dot([],[],A).

dot([H1|T1], [H2|T2], A) :-
  is(Anew,+(A,*(H1,H2))),
  dot(T1, T2, Anew).