Who was employed by M1 , employed by M3 's employee 's employer , and employed by M2
SELECT DISTINCT ?x0 WHERE {
?x0 a ns:people.person .
?x0 ns:people.person.employment_history/ns:business.employment_tenure.company ?x1 .
?x0 ns:people.person.employment_history/ns:business.employment_tenure.company M1 .
?x0 ns:people.person.employment_history/ns:business.employment_tenure.company M2 .
?x1 ns:business.employer.employees/ns:business.employment_tenure.person ?x2 .
?x2 ns:people.person.employment_history/ns:business.employment_tenure.company M3
}