John readily accepted the idea, and of course added a twist with the idea of projecting them. After a bit of head scratching and checking I agreed it could be done, thank goodness for the wiggle room (provided by the extra bit of length in the blocks) and the reduced height of the internal voussoirs. John also suggested we should have a tall keystone on the inside arches. The step increased the width of the wall, as did the increased curve at the top of the profile and the stones were not quite wide enough, so rather than finish at a point, they were in effect truncated, but even this imperfection worked and makes these keystones stand out even more I think.
I always liked the look of the original stepped voussoirs, although the regularity of the steps was a concern, as it would mean a lot of regular coursing, a lot of similar size stone and not a lot of space to manoeuvre this between the two doors on the inside and no basalt breaking up the stonework. To make life somewhat easier on the inside we had, sometime before this visit, settled on a simple curved arch, much less wasted stone compared to the original concept of having the motif front and back…but this wasted my initial calculations,
but a good decision on the whole, I think having all the internal arches over doors and seats ‘even’, makes it cohesive, and remove the necessity for completely regular coursing.
The keystones… did we have separate blocks for these? All I remember is that they were fraught with potential disaster
Personally I think the eventual design really sings, producing a striking motif, far better than I imagined at any point of the process, and I think in many ways they exemplify how this project worked in terms of design, tweaking and execution. An incredble symbiosis of ideas and designs, where we made changes with very quick additional tweaks and realisation of what was going to work. Conceivably we were just making it up as we went along and just lucky. Alternatively we always seemed to know where it was going sometimes singing different songs (lyrics) but always to the same tune and often producing interesting harmonies. I think that we usually work like this , but somehow on this project for me it felt as if it really came together in spades."
