'Dunno where to start . Does anybody actually accept any of this ?'
Well you could work outwards from Silbury Hill, making isocles triangles up as you go - sadly I never got the hang of geometry...there's Marlborough mound and the other one, almost really a bit like pyramid building, which are'nt isocles shaped because they have four sides... I like Silbury as a gnomon best, a large post on top telling the time of day...