[sdiy] Substitute for pin matrixes?

[Cary Roberts]

Instead of reinventing the wheel we should look to history.  Most of these
matrices can be fashioned in the garage with basic woodworking tools.

-Cary


Patent 229757

	http://www.google.com/patents/about?id=YExrAAAAEBAJ


Patent 234432

	http://www.google.com/patents/about?id=c7xxAAAAEBAJ


Patent 249445

	http://www.google.com/patents/about?id=44tRAAAAEBAJ


Patent 246343

	http://www.google.com/patents/about?id=9m5MAAAAEBAJ



Patent 255056

	http://www.google.com/patents/about?id=-uBaAAAAEBAJ



Patent 261187

	http://www.google.com/patents/about?id=TSZlAAAAEBAJ