A letter by Serhiy Grabarchuk on Paper folding problems

Some interesting info on Stamp Foldings can be found at:
http://www.theory.csc.uvic.ca/~cos/inf/perm/StampFolding.html .

We have at Puzzles.com a growing collection of different
folding puzzles; see our PuzzlePLAYGROUNG sector:
http://www.puzzles.com/PuzzlePlayground/Folding.htm .

Also we have one puzzle - The Origami Checkerboard Puzzle - at:
http://www.puzzles.com/PuzzleClub/CheckeredOrigami/CheckeredOrigami.html .

There are two sites with many additional challenges to
this puzzle. These are Origami Checkerboard Puzzles at
the OrigamiUSA site:
http://www.origami-usa.org/puzzles%202.htm , and

Sasaki's Puzzles at the British Origami Society site:
http://www.worthhall.demon.co.uk/fun/sasaki.htm .

At the OrigamiUSA you can also see another type of Origami
puzzles - Origami Area Puzzles:
http://www.origami-usa.org/puzzles%201.htm .

In November of 2000 Ed Pegg Jr. published at his site
www.mathpuzzle.com Junk's Origamic puzzle (or Junk Kato's
Triangle); now you can find a few solutions to it and some
further links on the theme at:
http://www.mathpuzzle.com/katotriangle.htm .

There are different well-known Flexagons described in Martin
Gardner's columns and books. See for example:
http://home.xnet.com/~aak/hexahexa.html .

Also add to the list one of the best folding puzzles ever - Arthur
Stone's Flexatube:
http://mathworld.wolfram.com/Flexatube.html .

A clever Origami puzzle seen from one more point of view is
proposed at:
http://home.istar.ca/~wko/origami_puzzle.html .

A clever combination of the Tangram pattern and Origami -
Tangram Folding - is shown at:
http://www.thok.dk/tangram.html . It's more like a piece of art,

At Sy Chen's Paper Folding Page
( http://users.erols.com/sychen1/pprfld.html ) you can see
a well-known philisophycal and puzzling symbol folded of
a single Origami b/w sheet:
http://users.erols.com/sychen1/Photos/jpg/TaiChi.jpg .

There you can see also Tangram Square folded using just a square
of paper:
http://users.erols.com/sychen1/Photos/jpg/TangramSquare.jpg .

Many different folding puzzles you can find in Martin Gardner's
books. For example see Wheels, Life, and other Mathematical
Amusements, Chapter 7, The Combinatorics of Paper Folding,
pp. 60-73. It contains a lot of folding puzzles and a further

Also there is a small but fascinating book Paperfolding Puzzles
by David Mitchell, published by Water Trade. Just 48 pages,
but with plenty of folding puzzles. This is the only book showing
seven different solutions to the Flexatube!!

Unfortunately I've just seen this great tiny book in a puzzle
collection some years ago. And there is a question - does anybody
has an extra copy of the Paperfolding Puzzles book to sell or trade?

There is a lot of puzzles made by folding of paper like Origami
models, but this is another theme...