Which art director was employed by a production company and was employed by M1
SELECT DISTINCT ?x0 WHERE {
?x0 a ns:film.film_art_director .
?x0 ns:people.person.employment_history/ns:business.employment_tenure.company ?x1 .
?x0 ns:people.person.employment_history/ns:business.employment_tenure.company M1 .
?x1 a ns:film.production_company
}