This is a two story Pompeii house. You want to mark each side of the box first, for the line where the top and bottom floors meet. Measure carefully because these are the two “floors” of your Pompeii house and they must meet at the corners. The top “floor”is smallest, and the bottom street-level part the largest. This gives a very nice illusion of perspective. You want a line at 7 inches, measuring from the bottom. On the sides, you want to continue the “roof” line from the front as well, On my box, which comes from Steve Harvey Miniatures, that line is exactly 4 and 1/8th inches above the line you made to mark the bottom of the second story. This box is sturdy & well-proportioned for the illusion of architecture.