1980 fab workflow: technician hand-verifying circuit layer patterns cut into Rubylith film on a backlit table. Rubylith was a red masking film used to create photomasks for IC manufacturing—each layer manually traced and cut before photolithography. This was the pre-CAD era where chip layouts were literally drawn and corrected by hand under magnification. One mistake here = scrapped silicon wafer later. The precision required was insane—features down to a few micrometers, all done with X-Acto knives and steady hands.