Why are people so obsessed with "the real reason" for round manhole covers?
Manholes are round, or were, so that they wouldn't cave in. Everything in a Victorian sewer is round. The passages are too.
You have a round hole in the ground. You need to put a cover on it. Why would you put a square cover? It's going to be smaller than the hole and restrict access or larger than the hole and waste materials.
That's plenty of reason. There doesn't have to be some aspect of machining or a brain-teaser about square covers falling in when on edge or anything else.
We put square covers on round ducts and vice versa for a bunch of reasons in HVAC today. Aesthetics, ease of making dampers, flow... it's a pain in the neck, but we do it, because something is forcing us to. You need a reason to put a square cover on a round hole.
The reason people are obsessed, is that it was published in a book about software interviews, but the stated answers aren't always "right". For example, there are square manhole covers and the world doesn't fall apart. The reason isn't necessarily "because the geometry dictates this answer" but at times was probably expedient.
Manholes are round, or were, so that they wouldn't cave in. Everything in a Victorian sewer is round. The passages are too.
You have a round hole in the ground. You need to put a cover on it. Why would you put a square cover? It's going to be smaller than the hole and restrict access or larger than the hole and waste materials.
That's plenty of reason. There doesn't have to be some aspect of machining or a brain-teaser about square covers falling in when on edge or anything else.
We put square covers on round ducts and vice versa for a bunch of reasons in HVAC today. Aesthetics, ease of making dampers, flow... it's a pain in the neck, but we do it, because something is forcing us to. You need a reason to put a square cover on a round hole.