Colourful Residential LifeThere is something special for the residential life at Yale: the residential systems for undergraduates and postgraduates operate differently.While it is a necessity for freshmen to live on campus,postgraduates enjoy the freedom to choose where they prefer to live, either on campus or outside.Yale's residential college system which is more than seventy years old is perhaps the most distinctive feature of the College.The twelve residential colleges allow students to experience the cohesiveness and intimacy of a small schoolwhile still enjoying the cultural and scholarly resources of a large university;it is in this sense that each college is a microcosm of the larger student population.The twelve residential colleges all have their own master and deanwho live in the college with their families and eat their meals with students in the dining hall.Freshmen are required to live on campus and they live on single-sex floors.Before freshman year, all incoming undergraduates are assigned to one of the twelve residential collegesby the individual college deans with two considerations in mind: compatibility and diversity.While students are matched based on general living habits, they should look forward to encountering a slice of Yale's diversity in their suites.After freshman year, students choose their roommates and obtain rooms through lotteries held by their colleges.