 For example, in a building with floors labeled G, M, 1, 2, ..., 11 and 12, the 4th room in each of those floors could be numbered 104, 114, 124, 134, ..., 224, and 234, respectively — with an offset of 11 in the floor numbers.This trick is sometimes used to make the floor number slightly less obvious, e.g.for security or marketing reasons.