This is a lovely picture but the rectangle is not the main image of the photo. It does make a nice frame for the photo and if the title were something like "Rear weindow rectangular frame" I would have associated the rectangle with the challenge and given it a higher 6 score.
Rectangles and squares and a beautiful model .. hard to go wrong with that combination! I like how 2 of the windows are outlined in a darker color too. Nicely photographed and good choice using b&w. 7