Here is the finished drawing. Reminds me so much of the barn we had on our home farm!
I have let the shingles draw themselves. If I work too hard on them, I seem to lose the freshness of the pencil strokes so I have let go and they seemed to just draw themselves. The most difficult is keeping them aligned with the roof line.
I think anyone who enjoys drawing barns will eventually draw a classic detail of a cupola. Here is a very ornate cupola I found recently on a barn.