The dog-legged staircase is one of the simplest forms of stairs in which a flight of stairs goes up to a half step before turning 180 degrees and continuing upwards. It is also called Dog Legged Staircase, because of its appearance in sectional elevation. It is a very common and popular type of staircase and is used in public and residential buildings. It consists of two flights that run in opposite directions, separated by a landing in the middle space or a quarter in space and a set of rollers.