It is easier to replace a circular cover, since you don't have to worry about it...

		biotech on April 20, 2009 \| parent \| context \| favorite \| on: Round manhole covers, or if Feynman applied for a ... It is easier to replace a circular cover, since you don't have to worry about it's orientation. I suspect that this is the main reason to use a circular manhole cover over some other shape.