the property which devel.but claimed to be the reason why that
strategy works. A bit of thought revealed what the _real_ reason is
why this strategy works in some puzzles and not others, so I've
rewritten the paragraph to be more accurate.
[originally from svn r6158]
B and some from me. Also an additional utility function
`random_copy' from Richard B, which he says is useful in a new
puzzle he's working on and which seems likely to come in handy again
at some point.
[originally from svn r6153]
