[Constitutions Grandchild]

Other than my answer, the only two I might entertain are the last two, but they beg the question. If you asked why MAN-HOLES are round, that's another subject altogether. The only answer I could come up with is that pipes are round and man-holes connect to pipes and are not prone to having debris lodge in corners.

[Hodar]

Also, if you are running cable or a series of connected pipes, there is a lower liklihood of a joint snagging on a round hole, rather than catching a corner of a rectangular hole.

But, the point of this exercise is that it demands that a person envision the problem in his head, rather than spin off some pre-canned answers. If you can envisiona problem, and think of solutions - you are NOT a typical academic.

Very different mind-set - this works well for engineers.