Here are a couple projects by Pb Elemental that employ L-shaped openings comprised of a horizontal and a vertical window. I'm not exactly sure what is going on inside, but it can be seen here that the vertical window is operable. Assuming the horizontal window is fixed, this means that the ventilation has more vertical spread — one can sit by the window to catch a breeze, for example.
Love square slabs with grass in-between. Geometrically pleasing to the eye and a break from grass yard. Open for breakfast table, fountain, etc. Cuts cost on watering