A more recent way of gaining more space in small houses is the box dormer, replacing an area of sloped roofing with flat to give more headroom : more convenient, but nothing like as attractive as the old-type small dormers. They're very common, though, so this adds extra variations for those who are modelling more recent times. Double-sided again: make your own choice of height and depth placement for further variety. Screenshot shows the two faces on each side of butt and ben no. 3