Which film did a person executive produce and M1 and M2 write
SELECT DISTINCT ?x0 WHERE {
?x0 a ns:film.film .
?x0 ns:film.film.executive_produced_by ?x1 .
?x0 ns:film.film.written_by M1 .
?x0 ns:film.film.written_by M2 .
?x1 a ns:people.person
}