What person that played M3 and M4 was a writer of M1 and M2
SELECT DISTINCT ?x0 WHERE {
?x0 a ns:people.person .
?x0 ns:film.actor.film/ns:film.performance.character M3 .
?x0 ns:film.actor.film/ns:film.performance.character M4 .
?x0 ns:film.writer.film M1 .
?x0 ns:film.writer.film M2
}