I really wasn’t sure what to expect with these plastic crafts. In this book, plastic crafts are clear acrylic items that end up being sign holders, shelves, and other basic containers. I thought these things were churned out by Big Plastic Factory and not something one would craft. The clear plastic theme was indeed a thing back in the day for the really modern look. If you are a librarian, you probably have a hundred of these things to hold the latest signs, flyers, etc for your library.
Looking at the detail involved, it does require some skill. Nowadays, someone would probably use a 3-D printer and call it a day.