Итеративно търсене по нива (Iterative deepening)
iterative_deepening1(Depth,Stack,Goal,Path,Max):-
depth_bound(Depth,Stack,Goal,Path).
iterative_deepening1(Depth,Stack,Goal,Path,Max):-
Depth =< Max,!, iterative_deepening1(Depth1,Stack,Goal,Path,Max).