My stroll today focused on a few blocks on the Left Bank a bit east of the Musee d'Orsay, in the art district of St Germain des Pres. Since some shops prefer that pictures not be taken of displayed original works of art (for obvious reasons), my attention soon turned to narrow lanes and finally to those fascinating entryways for cars and pedestrians which provide access from the sidewalk, underneath the first floor (not ground level), into an open central courtyard. At one point in its history, the more wealthy citizens of Paris revived the old Roman plan of providing multiple levels of housing with air and sunlight not only from the front, but also from a courtyard which was open to the sky and surrounded on all sides of the building's rooms. (Most of Oxford's colleges use a form of this medieval plan, greatly expanded.) The entryways' heavy double doors are normally closed and locked, providing a high level of privacy to the occupants. Fortunately, just a few were open this afternoon--a car had just pulled in, workmen were coming and going, a delivery was being made--and I caught a glimpse of these brightly lit courtyards through the long tunnels.