Looking Forward to Monday Morning
A series of essays on business, architecture, and the business of architecture.
Why are Manhole Covers Round
by Daniel Frisch
Posted May 12th, 2019

Come visit us on Fifty-Sixth Street and you will find hanging behind my desk a full-size color rubbing of a NYC sewer manhole cover.  Produced by an artist-friend in the early nineties, the piece of art is one of my favorites.  Not only do I admire the image, and the story of its creation, it has also become a mute accomplice when interviewing potential employees.  Many have heard the urban legends surrounding Microsoft and Google math riddles designed to keep interviewees on their toes and to help decide which of the Mensa candidates to hire.

For our interviews, I borrowed a question from a cousin who runs a private company here in Manhattan: “why are manhole covers round?”  Most recent graduates coming to interview at DFA have not heard the question and become off-balance; maybe not as much as “tell us about your five-year plan,” though perhaps they should be.  Imagine being twenty-something, sitting in an office with a middle-aged architect and a couple of associates at a firm where you would like to secure a job offer, and being asked why manhole covers are round.  On the surface, the question is simple and seems like something a prospect with a degree from a top-tier architecture school might be expected to know, and yet, most don’t.

When a candidate doesn’t know the answer, he or she must make a series of quick decisions, including trying to figure out the question’s context.  Why has this question been asked, instead of something about my portfolio, academic accomplishments or career goals?  Very often, the first response is to ask if the question could be repeated.  Next comes the guessing game. The two most frequent guesses are that round covers can be rolled from place a to b, or that a round manhole cover would save material over a square.  Both are true, but neither is the real reason.  Only once in a great while can a candidate figure on the spot, even with prompting, that the reason is to save lives; round manhole covers cannot fall through the hole no matter which way they are oriented.

Provided the candidate does not come to the interview knowing the answer, nor is one of the few who quickly stumbles upon the answer, our conversation becomes very informative.  Going through the first couple of guesses goes quickly, and we can talk about how one solves a problem when the answer is “I don’t know.”  Most candidates are very uncomfortable admitting a lack of knowledge, as I am certain I would be if the roles were reversed.  What we like to see in a candidate who engages in a conversation filled with questions and follow-up questions. A robust back and forth is better than fielding ever further afield guesses or responding to a request to Google it.