🚀 go-pugleaf

Reidar J. Husmo (radar@grumpy) wrote:
: Robert Weinberg (robertw@informix.com) wrote:
: : Manhole covers are manufactured in circular shape, rather than oval or square, to  
: : satisfy one paramount condition.
: : 
: : What is the condition, and why does a circular shape satisfy it?
: : 
: : What other shapes would also satisfy the condition?
: : 
: Ok, lots of people have already given the correct answer(s) to the first
: question, so I won't bother with that.

Really?  I don't think so.  All the answers I've seen that appear to considered
correct assume that the shape is constant diameter.  Any shape will work iff the
lip or ledge of the hole is smaller than the smallest cross section of the lid.
ie. I could make a manhole with a wide enough lip to make sure any shape manhole
cover would not fall through.  Of course the usabiltiy of such a hole and cover
would become suspect.

Therfore doesn't the real answer have more to do with minimizing material
while maximizing the real hole area such that the cover won't fall through?

Jerry Donovan