Some come here to shit and stink;
I come here to sit and think.
-- anonymous graffiteur
For me, the quest for the perfect bathroom came to a head [as it were] in a Vienna-style Kaffeehaus on the lower Rhine. Having enjoyed a Milchkaffee und Kuchen I make my way to the men's room. Once inside, I am thunderstruck by the sight of three stalls with glass doors. The (unoccupied) thrones are in plain view and the question of how anyone could do his business in such a public setting immediately presents itself. To buy time, I turn to the urinals, which are arranged along the wall to the left, right below the showcases - glass again - holding Kaffeehaus merchandise. The urinals reinforce the sense that I am in the presence of thoughtful design. The urinals offer a play on the Dutch fly design. A lit candle is drawn in the sweet spot of minimum backsplash. Average-man is gently nudged to extinguish the flame. Now I just have to figure out the secret of the poop stalls.
I mutter to the man at the adjacent urinal (German men are allowed to mutter at each other in the bathroom without being suspected of not-there's-anything-wrong-with-it-ness) that the glass doors are incomprehensible. He mutters back that that these doors are indeed an abomination. Having overheard these mutterings, a third man cheerfully announces that he will reveal the secret. He enters the middle stall, locks the door, et voilà, the door becomes opaque.

Is the occupancy-sensitive door a mere curiosity or are we witnessing intelligent design? I think the latter. Entering an ordinary multi-potty bathroom, (wo)man faces a problem. As stall doors tend to be closed, the questions is 'which ones are unlocked?' The hawk-eyed can see from a distance if the little color patch is green (yes) or red (no). Those with ordinary vision have to come closer for inspection or perform the ignominious bend-over to see if shoes come into view. The glass door design solves this problem handily.
A cultural comparison comes to mind. In many American homes, bathroom doors, like other doors, are open. A closed door implies a locked door. There is little ambiguity for those looking to sit and think. German bathroom doors, however, like other doors, tend to be closed. The user needs to knock before proceeding (or press down the latch, assuming that a busy bathroom's door is not only closed but also locked). The glass door design might point a way for these two cultures to find common ground. A door can be open and closed at the same time, as it were, and awkward moments ("Anybody in there!?") can be avoided. Perhaps such a rapprochement is under way. Reliable sources assure me that there is at least one club in New York City that
sports a 20-stall bathroom of the type I saw in Germany.
Back in Köln, I wonder how the ancients met their scatological challenges. A short walk from the vitreous bathroom, the remains of the Roman city Colonia are being excavated. Among the rubble, there is a sign referring to a window through which feces were thrown into a deep shaft. The sign is notable because it is a rare example of the profane use of Hebrew. From fecal defenestration to window-like bathroom doors . . . I see creative continuity there.
Indulge me as I go off topic as an esprit d'escalier comes to mind. Why is it so hard to count the floors of a German building and why is the vocabulary so French (except for mezzanine)? As I ascend from the souterrain to the bel étage by way of the parterre, where in the name of god am I? The Germans resolved to interfere with vertical orientation within buildings, and the use of French lingo is only part of the ploy. There are two ways of counting. According to one, the Parterre is also the first Étage. One flight of stairs up, I am in the second Étage. One should leave it at that. Americans would like it, along with everyone else, including the Germans themselves. But no! The Teutonic mind insists on intricacy. According to the second way of counting, which is actually more prevalent than the first, the Parterre is the ground level. Going up one flight of stairs, I am in the first Stock (i.e., storey). This numbering depends on how many flights of stairs have been passed. Level or storey is also known as Geschoss, which happens to be the same word used for "projectile" or "missile." Oh well. To distinguish the first Étage from the first Stock, the latter is also called the first Obergeschoss (super-, above-, or over-Geschoss).
Are you still with me?
Things come to a head - again - in my favorite hotel in Frankfurt. Whereas my habitation was in the Parterre, or first Étage, last spring, this winter my room is two flights of stairs up, although my room number is in the one hundreds. One flight up is the first Obergeschoss, with numbers from 100 to 110. I am in the second Obergeschoss, number 123. This would be the third floor with a number in the three hundreds in most countries. Taking the stairs, and thus my time, this experience leads to - well - this esprit d'escalier.