To create symmetry in a room, the proportions and profiles on your window casings should match—or at least complement—those on your door surrounds. This is easy enough, considering windows share the same head and leg casings as doors. The only difference is that windows have a fourth side, a bottom ledge consisting of the stool (or sill) and the apron. The stool is basically a shelf that extends out into the room, and beyond the width of the legs by an inch or so. The stool can be finished in several ways—for instance, with a simple square cut (as on the Arts and Crafts?style casing shown above) or with a rounded edge for a graceful return. The apron runs directly under the stool and is usually cut flush with the leg casings' outer edges.