VA 376 is a good example of how rectangles being omitted from TM makes a difference. VA 376 is posted from 3 entrances but 2 are rectangles only.
In VA 217's case, the circle is posted in at least 3 places, plus the State St spoke is posted at VA 16. I haven't been on VA 217 in over 10 years but I don't believe any of the other spokes is posted. Thus it is possible to have one spoke and the entire circle as one route.
In the queue.