:-object hello.
        var count=0.
		hello :-
                repeat,
                        format('hello ~w~n', [count]),
                        sleep(500),
                        ++ count,
                count > 10,
                !.
:-end_object hello.

:-object world.
        var count=0.
        world :-
                repeat,
                        format('world ~w~n', [count]),
                        sleep(250),
                        ++ count,
                count > 10,
                !.
:-end_object world.

:-object hello_world.
        main :-
                _H := new(hello),
                _W := new(world).
:-end_object hello_world.