Inspired by all the amazing stone work I saw on a visit to Palma de Mallorca, the capital of the Balearic Island Mallorca (Spain), I started paying attention to how the voussoirs of these vaults were cut. I did need inspiration to solve the problematic issue in the previous version of the vault, its cutting pattern.
Looking up at all the stunning stone vaults taught me a lot about Stereotomy (= The science or art of cutting solids into certain figures or sections, as arches, and the like; especially, the art of stonecutting – http://www.thefreedictionary.com/Stereotomy). In the previous try, L-shaped pieces were avoided since it was thought that those would appear awkward. In fact, it can be seen on the previous image that these L-shape pieces allow to nicely turn the corner over a groin and visually (and structurally) tie the entire vault together.
This image shows how to nicely morph from a groin vault into an elliptical vault. The stereotomy language/logic shown in this curving, vaulted arcade gives an important clue how we could transition between the different recognizable parts of our vault.