Very interesting Mr S.

Actually, and going off at a tangent, the ball and socket joints at Stonehenge are ball and socket joints because of the material (stone) that needed ‘jointing’. Put another way, it would be pointless (and far more time consuming) to attempt creating the angular mortise and tenon joints found in the woodworking tradition. Ditto trying to carve ball and socket joints into wood – it would be both pointless and difficult because the different materials of wood and stone lend themselves to different jointing solutions.

Which brings us to the important point that the ball and socket joints at Stonehenge might not have evolved from an earlier (wood-based) mortise and tenon tradition at all but were there right from the beginning – perhaps even preceding the (wood) mortise and tenon tradition itself?