Did M3 marry M4 and marry a person that wrote M1 and M2
SELECT count(*) WHERE {
?x0 a ns:people.person .
?x0 ns:film.writer.film M1 .
?x0 ns:film.writer.film M2 .
FILTER ( M3 != ?x0 ) .
FILTER ( M3 != M4 ) .
M3 ns:people.person.spouse_s/ns:people.marriage.spouse|ns:fictional_universe.fictional_character.married_to/ns:fictional_universe.marriage_of_fictional_characters.spouses ?x0 .
M3 ns:people.person.spouse_s/ns:people.marriage.spouse|ns:fictional_universe.fictional_character.married_to/ns:fictional_universe.marriage_of_fictional_characters.spouses M4
}