question: What film producer employed M1 , was founded by a producer of M4 's prequel , and employed M2 and M3
query: SELECT DISTINCT ?x0 WHERE {
  ?x0 a ns:film.producer .
  ?x0 ns:business.employer.employees/ns:business.employment_tenure.person M1 .
  ?x0 ns:business.employer.employees/ns:business.employment_tenure.person M2 .
  ?x0 ns:business.employer.employees/ns:business.employment_tenure.person M3 .
  ?x0 ns:organization.organization.founders ?x1 .
  ?x1 ns:film.producer.film|ns:film.production_company.films ?x2 .
  ?x2 ns:film.film.sequel M4
  }