By Meredith Blake, Special to the Los Angeles Times Over the course of four seasons, "Mad Men" has repeatedly used enclosed spaces -- elevators, closets, backseats -- to re-enforce the themes of secrecy, repression and isolation that are central to the show. But as the show has moved from the twilight of the Eisenhower era into the more permissive mid-1960s, these dark corners have slowly begun to transform. Here's a guided tour of the show's most notable tight spots, with some assistance from "Mad Men" cinematographer, Chris Manley. RELATED: In 'Mad Men,' fewer places to hide (AMC)