Was a film written by a writer and star of M2 and written by M1
SELECT count(*) WHERE {
?x0 a ns:film.film .
?x0 ns:film.film.written_by ?x1 .
?x0 ns:film.film.written_by M1 .
?x1 ns:film.actor.film/ns:film.performance.film M2 .
?x1 ns:film.writer.film M2
}