We needed to take down the old plaster for a section of the wall, because it was in bad shape. This is what I found when I knocked it down:
This is a "behind-the-scenes" part of a fireplace in an adjoining room, but the geometry of it is just awesome. The dirty grey string is the original plumb line used when the house was built!
Still in progress:
Can't wait to be able to show you AFTER...