@jacobsimmering Here is a story I haven't shared. In the late 1970s I had a job doing custom software installations on IBM mainframes. I had to go to the customer's mainframe and tinker with our software so it would install correctly. So there was a steel mill in Gary Indiana where I had to go. This was back in the day when America still had a lot of manufacturing, steel foundries, and so forth, and before there were laws about curbing pollution. For some reason, I was in Indianapolis at the time, rented a car and drove to the site. As I approached Gary, the sky started turning dark, but not because of a storm. The pollution was so thick, it was just normal. Quite striking and amazing. People who now take things for granted just don't realize how bad it was back then -- excepting current residents of Beijing or Delhi, who now experience similar. Oh, and when I arrived at the mill, I had to wear a hardhat and follow a very specific road to get to the computer room. I later learned that doing inventory in such places can be tricky - like when steel is molten, it becomes hard to track inputs along the manufacturing process.