Nowadays, there's an app for finding where rooms are, and the old plans are being replaced. This is becoming increasingly necessary because construction work has changed the layout of the buildings over the years.
On the left is what the app shows for the end of corridor 4B, which was known as the AI Corridor when I was a student. My office is 4B.529 .
On the right is what the layout originally was.
4B.531 was a common room, although officially it was called a seminar room so as to get it past the university's regulations about common rooms. It had a sink and a kettle and a fridge and a whiteboard and comfy chairs. Undergraduates could hang out there and interact with lecturers who went in to make a cuppa. It was an excellent resource, but sadly it didn't scale up. The more students we gained, the more people went in there, which had the rather unintuitive effect of reducing socialising rather than increasing it. The addition of a microwave cooker was the beginning of the end. People began eating lunch there and stinking the place out for much of the afternoon with overpowering food smells. When space utilisation became a university-wide issue, departments were charged more per square metre in an effort to get them to make better use of their resources, and that's when the common room was turned into a lab.
4B.532 used to be a teaching room under Computer Science's control, but the Timetable Office wanted to put lectures from other departments there so it was also turned into a lab. This put the rooms between the two labs in a kind of no-man's land, so eventually the interior walls were removed and they were made part of what is now Lab 4.
I shall miss the old maps.
When I was a PhD student, my office was 4B.533 .