Variable fonts a cool. I first learned about them at Adobe MAX in 2016. There was a session with people from Adobe TypeKit. Only about 10 people showed up. Granted, it was one of the last sessions of the conference and type isn’t something a lot of designers care about.
I made this in Glyphs. I’m far from being a competent type designer, but I’ve found the best way to understand things is to try to make them. I only drew a few characters and they’re poorly drawn.