This is a great hand-drawn diagram that shows how basic automotive systems work. Each part is labeled with a line & text and color coded.
Kind of wild that before computers, all engineering from cars, engines, turbines, to the full SR-71 were designed with a pen and paper!
Being able to draw used to be an extremely valuable skill.
Now you can design most things with a computer without any specific drawing ability.
The next big skill will be directing AI to come up with the designs your want.