A few times a year, something on Youtube catches my eye and I think it's worth bringing to your attention. Sometimes the video relates to technology and the internet, but this time it most definitely does not. It's actually in black and white, and dates from the 1930s.
It's an educational film that explains, and demonstrates, the workings and evolution of the differential gear. It's the bit of clever engineering in your car that allows for the wheels on one side to turn faster than those on the other, when you steer around a corner. And it was all developed without the aid of a CAD package.
If you can spare 9 minutes of your time, I can promise you a fascinating insight into how we used to design things (and explain them to others).
Check out https://www.youtube.com/watch?v=K4JhruinbWc and you'll see what I mean.
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