Bulbs in parallel

A little story: Seeing the tinkertoy computer reminds me of the mechanical "Computer" I got for Christmas when I was about 7 years old (1961..ish). It was a long long time ago and my memory could be a little distorted but, as I recall: It was made primarily of plastic and was about a foot long, 6 inches high, and 6 inches deep. This "toy" was built in horizontal layers or "planes" where each plane was one bit in the computer. The planes could slide either to the right or left to represent the logic states. If the plane was in the leftmost position, it represented a "0". If the plane was in the rightmost position, it represented a "1". I believe there were about 4 planes total. There was a "flag" (literally a flag) attached to the left end of each plane that provided the output. As the machine was cycled, the flags would raise and lower with the change in states. Along the rear of the computer there were a series of vertical wires that pushed the planes either to the right or to the left. These wires were the logic "gates" that drove the computer. As I recall there were about 8 of the wires (gates) in total. There were small projections from the rear of each plane that interacted with the wires (gates). To program the computer you placed small sections of a plastic soda straw, about 1" long, on some of the projections. The straws provided the input for each of the gates. If a straw was on one of the projections, it would interact with the wire (logical 1). If there was no straw on the projection, the wire would not touch the projection (logical 0). To operate the computer, the user would move a selected plane from one state to another. Any straws attached to the projections on that plane would push against the wires (gates) which in turn would push against the other planes in the machine. Some of the planes would change states, some would not. For each cycle of the machine, the user had to program in the next instruction. This meant moving around the straws on the back of the machine. Once the next instruction was loaded, the plane was slid back the other way. I never thought about it before but, this thing actually got two instructions per clock cycle. Max clock speed was about .01 CPS :-) The manual had detailed instructions for playing TIC-TAC-TOE and it actually worked. Unfortunately, it did not provide enough other examples so, I could never figure out how to make my own programs :-( I'm still fascinated by mechanical computers! Steve Robertson - QA Team Leader <steverob(a)hotoffice.com> Don't our "Queen's English" friends (uk and au) call it "naughts and crosses"?