question: Who wrote and directed M1 and M2
query: SELECT DISTINCT ?x0 WHERE {
  ?x0 a ns:people.person .
  ?x0 ns:film.director.film M1 .
  ?x0 ns:film.director.film M2 .
  ?x0 ns:film.writer.film M1 .
  ?x0 ns:film.writer.film M2
  }