As an “enterprise” developer in the 80’s, we all had beepers to go along with our suits and ties. People often thought we must be doctors, but we were just corporate mainframe developers.
I worked for a few banks starting in the 1980’s. It was all MVS. End user applications were created using CICS and IMS. What we used to call OLTP (online transaction processing).
Here's the U.S. Naval Academy's guide to the rules of the road.[1] Section C has the lights. For most ships and boats, it's reasonably simple - red, green, and white visible in 120 degree arcs, with white visible from the rear, plus a high white masthead light for some vessels. The complicated cases mostly involve work boats doing something - fishing, cable-laying, towing, etc.- where there is a hazardous area around the vessel and movements are restricted.
I have made many flutes out of pvc. Shakuhachi, bansuri, Ney, are all good to make in pvc. I have also made recorder style, using a shaped cedar plug on the mouth end.
