What German art director directed M2 and M3 and directed M4
SELECT DISTINCT ?x0 WHERE {
?x0 a ns:film.film_art_director .
?x0 ns:film.director.film M2 .
?x0 ns:film.director.film M3 .
?x0 ns:film.director.film M4 .
?x0 ns:people.person.nationality ns:m.0345h
}