Sorry, this was accidentally sent before it was completed. At 04:40 PM 2/13/2015, Tom Sparks wrote: I built a greatly scaled down version of Simon more than 50 years ago. See Chapter 3 in: Edmund Callis Berkeley Giant Brains, or Machines That Think New York: John Wiley & Sons, Inc., 1949; Reprinted New York, Science Editions, Inc., 1961 Available in DejaVu format at: https://ia600504.us.archive.org/17/items/GiantBrains/giant_brains.djvu Dale H. Cook, GR / HP Collector, Roanoke/Lynchburg, VA http://plymouthcolony.net/starcity/radios/index.html