Off the top of my head, I thought that they'd be easier to lay (the manhole covers, not the elephants or the chorus line) as they have rotational symmetry - whichever way you try to put them in the hole, they will fit. This isn't true for many alternative shapes.
A similar point occurred - that they are also easier to move around (being, essentially, wheels) - but then I thought that might represent a danger, even if it made life easier when it works...
Originally posted by Daemon Sin...and this isn't as facetious as it might first appear - the manholes are round because (presumably - I haven't been down many manholes) the 'tunnel' underneath is a cylinder - which would be a usefully robust shape to make the access tunnel...
Because manholes are round...
Originally posted by DrKFMore to the point, what you can't do with a round manhole cover is rotate it so that you can drop it down the whole...
Off the top of my head, I thought that they'd be easier to lay (the manhole covers, not the elephants or the chorus line) as they have rotational symmetry - whichever way you try to put them in the hole, they will fit.
This was one of my favorite job interview questions. Amazing the answers you might get!
The most important reason (mentioned several times) is that "round" is the only shape where the (heavy and dangerous) cover could not be accidentally dropped through the hole.
Other obvious answers include cost and weight minimization, the ability to easily move by rolling, the avoidance of sharp edges, the "roundness" of the human body.
Yet it is surprising how many manhole covers you see that are square!
Originally posted by AetheraelI heard similar. Whats the difference between a circus and a brothel?...One has cunning stunts and the other doesn't
I've always heard this as "what's the difference between an acrobatics act and a chorus line..." one's a cunning array of stunts...
The best thing about the joke though was when a colleague of mine told it at a dinner party. She had no sense of humour, didnt get it but wanted something amusing to say at the dinner, so a friend of mine suggested the above joke. However the version she told was...
Whats the difference between a circus and a brothel?...One has a lot of clever tricks