CREATE TABLE projects (code VARCHAR, name VARCHAR)
CREATE TABLE scientists (name VARCHAR, SSN VARCHAR)
CREATE TABLE assignedto (project VARCHAR, scientist VARCHAR)

Find the name of the scientist who worked on both a project named 'Matter of Time' and a project named 'A Puzzling Parallax'.
SELECT T3.name FROM assignedto AS T1 JOIN projects AS T2 ON T1.project = T2.code JOIN scientists AS T3 ON T1.scientist = T3.SSN WHERE T2.name = 'Matter of Time' INTERSECT SELECT T3.name FROM assignedto AS T1 JOIN projects AS T2 ON T1.project = T2.code JOIN scientists AS T3 ON T1.scientist = T3.SSN WHERE T2.name = 'A Puzzling Parallax'
SELECT "T3"."name" FROM "assignedto" AS "T1" JOIN "projects" AS "T2" ON "T1"."project" = "T2"."code" AND "T2"."name" = 'Matter of Time' JOIN "scientists" AS "T3" ON "T1"."scientist" = "T3"."SSN" INTERSECT SELECT "T3"."name" FROM "assignedto" AS "T1" JOIN "projects" AS "T2" ON "T1"."project" = "T2"."code" AND "T2"."name" = 'A Puzzling Parallax' JOIN "scientists" AS "T3" ON "T1"."scientist" = "T3"."SSN"