The Smithsonian has a great collection of industrial drawings, doodles and sketches, like this Electro-mechanical fly catcher from Everett Huckel Bickley (1943) – “Drawing is a key element in the process of working out ideas. Drawing moves an idea from the “mind’s eye” to paper, the first step along the path from thought to three-dimensional reality. Inventors sketch as they think, developing their ideas on paper more quickly and more easily than they might in model form.
The drawings in this section of the exhibition-from the proverbial sketch on a napkin to daily jottings in a notebook-show inventors considering engineering, economics, materials, and potential users as they think through new ideas.” Thanks Saul! – Link.