Has the patent on Penrose tilings run out?

Factual Questions
1

I have wasted a bunch of time designing some Penrose tiling artwork. Penrose tiling is a curious aperiodic tiling based on regular pentagons. Here is the Wiki page on the subject. I know that Pentaplex sued Kleenex some time ago for violating their patent law. What I want to know, is can I commercially exploit Penrose tiling on something like note cards? Would I be violating any patent or copyright laws? I had heard that the patent had run out recently, as commented about on this page, which also shows a very cool actual penrose floor tiling.

2

The patent:
http://www.google.com/patents?id=tjQ2AAAAEBAJ&dq=4133152

Issue date: Jan 9, 1979

So, it expired 17 years after that, or 1996.

3

how the hell do you patent something that has prior art of 1500 AD?

4

Thanks for finding that.

The patent office has been known to grant patents to some less than innovative ideas. However, the articles I’ve seen showing the Islamic tilings feature a different tile set as the Penrose tiling (they do share at least one or two as far as I can tell). I can never figure out what the criteria for a U.S. patent is anyhow, other than spending a lot of money for lawyers.

5

If Penrose tilings are non-repeating, that doesn’t work well for mass production of long rolls of paper - the rollers that emboss patterns on paper are only a yard or two in circumference, so the pattern on the paper will have a one to two yard repeat.

6

That’s what I was thinking. You might be able to break the aperiodicity by adding a transitional border that uses the same tiles but allows the pattern to repeat. An astute math nerd would probably notice the rules violation. I’ll have to play around with the idea. Of course, you could use a continuous roll inkjet printer and generate the patterns on the fly with a computer, but that would be a pretty expensive process.