What person wrote M1 , wrote M2 , directed M3 , and directed M4
SELECT DISTINCT ?x0 WHERE {
?x0 a ns:people.person .
?x0 ns:film.director.film M3 .
?x0 ns:film.director.film M4 .
?x0 ns:film.writer.film M1 .
?x0 ns:film.writer.film M2
}