I think it’s a joke about physicists not understanding tolerances.

I remember hearing an old story about a company buying signs from a contractor. The contractor produced all kinds of things, so it was fairly straightforward to send them the CAD file and stop worrying about it. One manager did an audit, and realized they were paying hundreds of dollars each for these basic signs. They weren’t fancy or anything, and were just signs throughout the facility that got updated regularly. So why the hell were they paying so much for what should have been a simple print job?

After some investigating, the manager discovered it was because the company didn’t want to hire an artist to design the signs; They just had one of their engineers do it. And the engineer who did the design forgot to change their default tolerances from 3/1000 of an inch. So to comply with the order as written, the contractor was busting out calipers and meticulously measuring the spacing and sizing on each letter before it shipped out the door.