A few unrelated ideas that popped into my head during the night and early morning... they're all things I think about regularly:
Make gold coins for use after governments collapse. Everybody can have their own mint. Leave a spot on each coin "clean" showing the crystal structure, and people can verify the authenticity by checking it against a photo on the Internet or Unternet.
For banking transactions, every detail needs to be saved to hardcopy for reconstruction after computer and network failures. A diamond stylus can be used to make marks representing ASCII in old metal strapping, fed by a worm gear or the like. Follower styli can verify the write in real-time.
Someday I've got to make myself understand how a sewing machine works, and design something handheld that accomplishes the same thing with solenoids or whatever. Unless someone's already done it? Googling so far has found nothing like what I'm looking for.
last updated 2013-01-10 21:11:19. served from tektonic.jcomeau.com