Since the title is a bit vague: this is a demo of the Mergenthaler Diagrammer, a tool for (semi-)automating the production of technical drawings like circuit schematics.<p>From a quick look this is what I ascertained: you select a diagram symbol using a keyboard, use a viewing screen (a specialized projector) to position it on the ”drawing”, and then once it’s in position the projected image is exposed onto film.<p>I’m a technically-minded artist/art historian who works a lot with projection, and this is a treat! What a great find!<p>If you like this you might also like Fran Blanche’s YouTube video about how the big screens at Apollo Mission Control worked.