The rule of Fourths

This is a window inside Mt. Vernon looking out. You can't take photos inside and I stole this one before anyone caught me. I think that's why it's a bit crooked! In design, the rule of thirds is important - and in photography too - you are supposed to put the "action" at the intersection of vertical and horizontal lines. Even though there is no action in this picture I like the contrast of black, white and gray and the geometry of it all.