Which actor was employed by M1 , employed by M2 , and employed by a film producer
SELECT DISTINCT ?x0 WHERE {
?x0 a ns:film.actor .
?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:film.producer
}