"Janet" <par### [at] attnet> wrote:

> Thank you Jon. I am amazed. I will play with it and try to understand it
> all.

If you (or anyone else) have any questions, just ask here (or in p.b.i) for
the next week or two, or send me an email.  Any comments on the code or its
output will help me tweak and tune to make it better.

As you may have noticed, I have this in version control on my system so I
can break it, and still get working copies back, etc.  It's already gone
through a bunch of revisions, so a few more won't hurt it. 8^)

I should say that all those decagons are due to a whim I had about 20 years
ago when I first read about Penrose Tiling.  Martin Gardner wrote that
there are 62 distinct decagons, only one of which can be filled.  I always
thought it might be interesting to have a complete set.  But if you count
them, you will see that there are only 56, although there are multiple
versions of some of them.

A short computer program I wrote told me that there were only 56, so I
wonder if there are 6 more that I missed, or if people have been quoting a
mistake for years and years.  I guess the way to verify it would be to
generate all 1024 decagons, and see which are reflections or rotations of
the others.  That's a bit too much for me, though, and it should be what my
little program did to get its answer of 56.

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