question: Were M1 , M2 , and M3 produced by a film 's sequel 's art director
query: SELECT count(*) WHERE {
  ?x0 ns:film.film_art_director.films_art_directed ?x1 .
  ?x1 ns:film.film.prequel ?x2 .
  ?x2 a ns:film.film .
  M1 ns:film.film.produced_by|ns:film.film.production_companies ?x0 .
  M2 ns:film.film.produced_by|ns:film.film.production_companies ?x0 .
  M3 ns:film.film.produced_by|ns:film.film.production_companies ?x0
  }