Was a art director employed by M1 and M2 and employed by a company
SELECT count(*) 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 .
?x0 ns:people.person.employment_history/ns:business.employment_tenure.company M2 .
?x1 a ns:business.employer
}