Combining the first and second interpretations of this theme, here’s a take with both the flanking skylights (a la Soane) and the semi-circular colonnade, with two large columns on center to flesh things out.
In typical fashion, a synthetic plan was due: taking the vault from yesterday’s post (my take on Lutyen’s take on Soane’s take on antiquity), I slapped a half-round colonnades on either end covered each in a large conical shingled roof. The fun part is the cornice of the cubic vaulted form, which does some funky things to accommodate modules, structure, and walls, shown in the bottom drawing (wormseye axonometric detail). The lantern is a direct quote of the lighthouse lantern at Old Point Loma in San Diego.
My wife and I drove the coast on our way back home from Portland, and we stumbled upon an lighthouse along the Coquille river in southern Oregon. I was struck by the simple forms rendered in white plaster: the tall cylindrical light and a low lozenge-shaped accessory building. These were both detailed in a pseudo-French collection of mannered profiles and mouldings, with large cyma-ed keystones and segmental arches, and iron king-rod trussed roof construction. Civic work today pales in comparison.