I have always liked domes, especially in 3D games. In my first level, The Hall of Sabers, I wanted to make the main chamber a massive dome. Oh boy... I tried cleaving in all different ways, and moving vertexes all over the place.... It turned out really horrible. Nothing ever lined up right and I ended up with non-convex sectors and faces galore! The other day (almost six months later) I was playing around with the room in JED and all of a sudden I realized how to do it!
My chamber began like this, as all new JED levels do:









