They can change direction without “dividing” them and without landings. Some of the steps have different width which allows them to change the direction of the flight. The width of the outer edge of the stairs is greater than the inside one—it should be at least 10 cm wide, whereas the middle of the flight, i.e. the middle of the tread, must be equal for all steps. This type of stairs works great for cramped rooms, because they take up less space than conventional two-flight stairs.