This repo is my own fork of Simon Tatham's portable puzzle collection,
the original version of which can be found (as of this writing) at
git://git.tartarus.org/simon/puzzles.git.  I am not forking it because
I think he's done anything wrong - quite the opposite! - but simply as
a place to keep the work I've done.  Some (all?) of it he probably
doesn't want to take back; the rest (if any) of it is here as a place
to keep it until he does pick it up.