Which screenwriter was a character employed by M2 and employed by M3
SELECT DISTINCT ?x0 WHERE {
?x0 a ns:fictional_universe.fictional_character .
?x0 a ns:film.writer .
?x0 ns:people.person.employment_history/ns:business.employment_tenure.company M2 .
?x0 ns:people.person.employment_history/ns:business.employment_tenure.company M3
}