I took it as a good humoured take ad I answered it in the same fashion.
I could, in fact, draw the entire thing on paper. Technical drawing was taugh to me in school and I took quite well to it; I still like to draw today but more as an artistic expression.
Although I wouldn't consider what I make as artistic under any light.
But my original still holds. Yes, I could. But I would have to make everything from scratch every single time we wanted to try an idea.
Not really practical.
I'm going to look into LibreCAD and FreeCAD. Seem to be the most promising solutions.