question: Were M3 and M4 written by a costume designer that M1 and M2 employed
query: SELECT count(*) WHERE {
  ?x0 a ns:film.film_costumer_designer .
  ?x0 ns:people.person.employment_history/ns:business.employment_tenure.company M1 .
  ?x0 ns:people.person.employment_history/ns:business.employment_tenure.company M2 .
  M3 ns:film.film.written_by ?x0 .
  M4 ns:film.film.written_by ?x0
  }