And yet if they ask you for an answer to a quirky question like "why are manhole covers round?", they expect a clever answer like "they can't fall in", rather than a pedestrian answer like "well, probably they just started making them that shape for some simple production reason, and then everyone else just kinda of did the same thing because it worked."
They aren't even all round in the US. Where I live there is a high and rapidly growing number of data centers. In fact there is currently another large data center campus being built for the company famous for asking this question. Among other things this means installation of fiber optic cabling along the roads leading to the data centers. This in turn means the installation of a large number of manholes to service the cables. All the covers for these manholes are rectangular.
Manhole covers come in a variety of shapes. A non-ironic "why are manhole covers round" question speaks more to lack of life and/or travel experience than anything else.
There are triangular[1] and even more exotic-shaped[2] covers.
Lots of man-hole covers are rectangular though. Turns out it isn't very important at all to have manhole covers that don't fall in. They are quite heavy and don't roll around on their own, so having them fall somewhere really is of minor concern.
My guess is it’s also a matter of practical usage: they’re made of heavy iron and a round one will fall in place whatever orientation it’s thrown over the cover, while a different shape needs to be carefully oriented. I suspect this also means less broken fingers.
But round one is easier to steal.. just roll them off. Whereas a square or any such shape, would be very inconvenient to move.
[Edit in response to a question]
Some people have attempted to steal manhole covers in order to sell them for scrap metal. China Daily notes that there has also been a problem with taxi drivers removing manhole covers to "steal water and clean their vehicles".
https://www.bbc.com/news/blogs-news-from-elsewhere-52400235
It's a very common thing to steal. Lots of iron. That's why they use concrete-filled ones. That's why they are stamped so a scrapyard can be checked (or alert authorities).
In my area there are lots of square manhole covers. I have it on my personal to-do list to photograph almost all the older manhole covers from my city and geo-locate them at some point, I think it could be a good indicator of how my city grew and evolved ~100 years ago.
Richard Feynman oversaw the IBM computer's use and programming used in the Manhattan Project. Microsoft also has an R&D department that would probably just give him a budget and a team of assistants to see what he came up with.
I don’t know but I shudder at the thought of what state the world would have to be in for Feynman to be interviewing at Microsoft or any FAANG company for that matter.
A bad interviewer might expect a certain answer but a good interviewer will use it as an opportunity to examine the interviewee's critical thinking skills.
Are there any other reasons the cover would be round? It gives you an insight into their thought process as they come up with more ideas and explanations.
