"Rope Punk", anyone? :-) Going back to the original theme of fictional worlds in which 20th century technology gets discovered in the 19th century, there's some sci fi novel (can someone provide a reference?) in which a white time traveler from South Africa travels back to the time of the Civil War and arms the Confederacy with anachronistic technology to help them win the war. One of the Union scientists trying to cope with the South's sudden possession of superior weaponry is perplexed by the sudden introduction of something that is recognizably a mature technology. I don't know whether the ability to recognize the difference between a mature technology and an immature one is itself anachronistic in the context of late 19th century engineering. Jim Propp On Saturday, September 13, 2014, Henry Baker <hbaker1@pipeline.com> wrote:
I spent a few moments with this paper (thanks for posting!) today & noticed that it showed only NOT, OR, AND, RS flipflop and "multiplex" gates.
Is there an elegant XOR in this logic system?
Also, it would be interesting to work out an _invertible_ rope&pulley logic system, much closer to (perhaps isomorphic to?) the billiard ball model.
Pulleys must be very, very old, as ships & ropes are very old. We know that the Greeks&Romans already had "odometers" in which the number of turns of a wheel would "count" a number of balls, or at least wind a certain amount of rope. Given that we now know they had sophisticated gear trains, it is conceivable that they also had sophisticated rope & pulley mechanisms.
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