On Tue, 20 Sep 2005 09:31:47 +0200, (Nick Müller)
wrote:


Here is my answer:
Hex once were square (and not called hex :-). They used to much space
(distance bolt hole - housing). The next step would have been a
pentagon.

Pentagons are used here as the utility companies standard for
shut-offs, especially below grade. Presumably to stop the
un-authorized actuation of these valves, either on or off.

Brian Lawson.
Bothwell, Ontario.