Paper-folding
Q: ??? Given a nice subset of the plane, is there a way to fold it (origami-style) that increases the circumference? What's the best definition of "nice" here?
What if we allow a general piecewise-isometric continuous map? Is
this the same thing (ie are there such maps which can't be produced by a
sequence of physical folds)?
rec.puzzles, 15 Apr 1996