Rooms in the main site are arranged along corridors, which makes it possible to walk from one location in the building to another without going outside. Some of the rooms originally designed as sets by Alfred Waterhouse. The rooms range in several quality grades but are all charged at the same weekly rate. Every year, a ballot is organised by the JCR to determine room distribution. To first years, rooms are allocated randomly. It is customary for Cambridge colleges to provide accommodation for the first three-year undergraduate students.