I found a Wikipedia article that expands on motivations for the design: Titulus_(fortification)
The description in the wiki article and the orientation of the diagrams on page 63 of the Keeley document convince me that the more common arrangement was to place the detatched screening wall segment on the exterior of the curtain with an interior version sometimes used either instead of or in addition to the exterior screen.
Edit: I think I read the pg63 diagram orientations wrong, so I think my point is mostly that it can be either inside or outside, and that this whole PDF is really cool.
I found a Wikipedia article that expands on motivations for the design: Titulus_(fortification)
The description in the wiki article and the orientation of the diagrams on page 63 of the Keeley document convince me that the
more common arrangement was to place the detatched screening wall segment on the exterior of the curtain with aninterior version sometimes used either instead of or in addition to the exterior screen.Edit: I think I read the pg63 diagram orientations wrong, so I think my point is mostly that it can be either inside or outside, and that this whole PDF is really cool.