Who was a art director of M1 , M2 , and M3
SELECT DISTINCT ?x0 WHERE {
?x0 a ns:people.person .
?x0 ns:film.film_art_director.films_art_directed M1 .
?x0 ns:film.film_art_director.films_art_directed M2 .
?x0 ns:film.film_art_director.films_art_directed M3
}