The walls are certainly curious... I've (crudely) drawn out the necessary conditions for either sitting or standing. Scheme A is the ideal configuration for seating as the "benches" are at the back of the "run" of each step allowing for people with "normal" size legs to be able to sit and have their feet touch to the front of the run of each step. Scheme A is not ideal for standing as there is really nothing to lean against in front of you to prevent you from falling into the row in front of you. HOWEVER, Scheme A is NOT currently how the images are showing the viewing area. The viewing are currently appears to be like Scheme B with the "benches" (or more appropriately, "walls") being at the front of each "run" of each step allowing for something to lean against in front of you. Scheme B is not ideal for sitting as the distance to the ground is much greater. With the steepness of the viewing area, if the intention was to stand, having something to lean against in front of you would be necessary, however, I'm curious (if this is the intention) why they would have made them so wide"? If these walls are for leaning, they could have been substantially more narrow (4"-6" as opposed to the perceived 10"-12") allowing for a substantially greater amount of area for standing.
Could the intention be to come back and fill in the area between the "wall" and the "rise" of each step (as in Scheme C) to make this more appropriate for seating? It could certainly explain why the front of the "rise" has no stone work.
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