Adesso Trackball T50 http://xahlee.info/kbd/adesso_trackball_t50.html
Navy Wants Knobs and Sliders, No Touchscreen http://xahlee.info/kbd/navy_touchscreen.html
the veritasium guy, self intro. very inspiring.
Pink Pather. I watched a lot around age 10. That's around 1980. I think i saw this one. 30 years ago.
#math Michael Atiyah died in January. i missed it.
this, you buy. real rotor. (not fixed pitch) powered by battery.
https://amzn.to/2GYRjm0 i've seen gas powered ones with much complex rotor
helicopter rotor mechanism animation https://www.youtube.com/watch?v=83h6QK-oJ4M
mstdn.io is one of the instance in the fediverse. We're an open-minded generalistic instance. Learn more here!