One of the ways I come to understand a building is to measure it and then draw it on paper. Using a tape measure, a clipboard and a pen to record the space inside and out is, for me, a way to spend time sensing the character of a place. Putting those dimensions on paper lets me revisit and more clearly know what I saw and felt.
So, I measured the front of the 1795 house, and put it on paper. Then I looked at what was there using the proportions of the square and the rectangle derived from its diagonal.
And there was the pattern - each side of the house was a square. The windows on each side were also symmetrically placed on each side of the center of the square. That square is the determining shape and dimension for this house. You can see the squares marked on the first drawing.
In the second drawing you can see the arcs derived from the diagonal of the square. They determine the size of the center bay. (Yes, they don't meet exactly. However, considering that they are only 6" or so off over a building 38 feet long, that's pretty close.)
I was delighted. I knew then how wide the entrance had been, and not just because I'm an experienced architect with an 'educated eye'.