The hacker in the bathroom

Readers with long memories might recall that I once wrote a post titled “The hotel bathroom puzzle,” which appeared on this blog about two and a half years ago. It was inspired by a case study that I had found in the book The Evolution of Useful Things by Henry Petroski, who took it in turn from Ralph Caplan’s By Design: Why There Are No Locks on the Bathroom Doors in the Hotel Louis XIV and Other Object Lessons. Since I’ve quoted Petroski’s version at length here before, here’s how Caplan originally told it:

An ingenious example of the product-situation cycle could once be found in a Quebec waterfront hotel called L’Hotel Louis XIV, lamentably destroyed by fire in the 1980s. At the Louis XIV, the term “private bath” meant what it means in many European hotels: the bath is yours but not yours alone, for it is also the private bath of the guest on the other side of the bathroom. This creates a problem. If the bathroom has no inside locks, you have no privacy. But if the doors can be locked from the inside, one forgetful guest can lock the other out indefinitely and almost surely will.

The hotel’s solution, Caplan reveals, was to tie a leather thong to the knob of each door. A guest who wanted to use the bathroom simply hooked the two ends together, stretching them across the room and holding both doors shut. As Caplan notes: “There was no way to get back into your own room without it at the same time unlocking the door for the other guest. It was memorable as the total integration of object and circumstance.”

This is the kind of story I love, so I threw together a post based on Petroski’s version, put it on the blog, and moved on. I couldn’t have spent more than an hour on it, but it got a favorable response from readers that morning, which is all it was ever supposed to do. Earlier this week, however, something unusual happened. I noticed an uptick in views for that page, which occasionally happens when somebody links to one of my old posts online. (This occurs a few times a year with my writeup on Blinn’s Law, which is another throwaway post that took on a life of its own.) It apparently began on Reddit, where a commenter linked to it in a thread for an unrelated story about sharing a bathroom with a sibling. Somebody else evidently posted the same link to Hacker News, the aggregator site associated with the startup incubator Y Combinator. From there, it took off. When I went to bed that night, it was the top post on the front page, and although it soon dropped a few notches, it had a surprising amount of staying power. It was widely shared on Twitter and Facebook, mostly from users who repost anything that gets a lot of upvotes, and it continued to snowball from there. As I write these words, it has over fifty thousand views, which is good enough to make it the second most popular post that I’ve ever published here, topped only by a piece about George R.R. Martin that will probably remain the most widely read thing I’ll ever write, thanks to a similar confluence of factors on social media. Whenever this happens, it fills me with both excitement and anxiety—you just never know where it might lead—but in both cases, I emerged mostly unscathed. There were a few nitpicky comments, but for the most part, people seem to have genuinely liked it.

So why did it catch on? Unlike Caplan and Petroski, who treat the anecdote as a straightforward case study, I framed it as a puzzle, which evidently appeals to the sort of crowd that you find hanging out on Hacker News. This wasn’t a conscious choice, but a result of the way in which I tend to write these posts, and it had a lot to do with the illustration. In The Evolution of Useful Things, Petroski reproduces a line drawing from Caplan’s book, which only shows the bathroom with the solution in place. Since I like to include two pictures with every post, it occurred to me to include a before and after shot. I quickly edited the picture in Seashore to remove the leather strap, and you can still see the traces of my hasty retouching. But the result was a post that looked sort of like one of those visual brainteasers that most of us read growing up, and I think that contributed to its appeal. (Looking back at it now, I see that the original picture in By Design was drawn expressly for the book by the legendary graphic designer Milton Glaser, who is apparently good friends with Caplan. Amusingly, the illustration is the one aspect of the post that generated any criticism, with one commenter complaining: “It’s a poor drawing. They look like doors that open inward. Doors that open outward would be need to be set more deeply into the door frame.”) As a result, it came across as an exercise for the reader, and the ensuing discussion was less about the actual solution at the Hotel Louis XIV and more about various approaches to the problem itself, which I don’t think would have happened if I had written it up as Caplan and Petroski did. This was purely by accident, but it’s interesting, at least to me.

And the thread that it inspired is worth reading. Among other things, it led to a number of useful critiques that had never occurred to me. (One commenter noted that such an arrangement would be hard to open from the outside in case of an emergency, although I think that this problem is more apparent than real. I don’t know what the exact setup was at the hotel, but the term “leather thong” suggests something roughly the thickness of a shoelace, which would present enough resistance to a casual tug to ensure short-term privacy, but would break at a sustained pull. Another reader asked how guests in one room could be prevented from entering the other, and the answer appears in a line from Petroski that I neglected to quote: “Each bathroom door did have a lock on the guest room side, of course, for otherwise a stranger could come in through the common bathroom, but there were no locks at all on the insides of the bathroom doors.”) Other replies were less useful, with some proposing solutions along the lines of motion sensors—“Tech is cool”—or raising persnickety objections: “What if the high humidity of the bathroom causes the leather strap to break at an inopportune time? What happens if the strap gets misplaced or stolen? This is not a good idea.” As the top comment put it:

I’m reminded of a discussion we had here a few weeks ago, where somebody noted that humanity wouldn’t be able to invent, for example, a machine to automatically rack pins at a bowling alley today. The 2018 solution to that problem would automatically involve computer vision, AI and robotics…You can see it happening in some of the comments here.

But there was also a lot of ingenuity and civilized discussion, which pleased me. This was mostly due to the power of the original example, but I think the way that I inadvertently structured the post—which encouraged speculation—had something to do with it, too. It may not quite qualify as “the total integration of object and circumstance.” But it wasn’t bad, either.

The limits of professionalism

When you are doing something in a recurring way to diminish risk, or doing it in the same way as you have done it before, it is clear why professionalism is not enough. After all, what is required in our field, more than anything else, is the continuous transgression. Professionalism does not allow for that, because transgression has to encompass the possibility of failure, and if you are professional, your instinct is not to fail—it is to repeat success. So professionalism as a lifetime aspiration is a limited goal.

—Milton Glaser