How the Curta Works
"Nine's complement arithmetic can be implemented in hardware by inverting the cogs on the step drum. Herzstark cleverly realized that a single step drum can be used to implement both normal addition and nine's complement addition by interleaving the normal and inverted cogs and moving the step drum up or down slightly to switch between them. [...] An additional row of ten teeth is added to the step drum to implement one plus the nine's complement of zero."
Tags: computers, mad science, mpegs, retrocomputing, toys
I have ported XScreenSaver to YouTube
Well, kinda. I made them all able to record MP4s of themselves, then uploaded a two minute HD clip of each. That's a lot of videos! The XScreenSaver screenshots page links to the videos, and there's a playlist.
Downfracking the Mandelbrot
William Wood:
Downfracking had opened universe after universe of ever-more-pure resources. The farther downfractal you traveled, the simpler the universe and the more you tended to slide backwards along the time axis. Each fractal was a perfect copy, from a distance, but simpler, and because they were simpler, those resources had fewer contaminants. Water had less impurities. Diamonds, less inclusions. Hell even the shit smelled like roses--well, not really, but that was the joke they all laughed at even though it wasn't funny anymore.
