L-systems are a lot of fun. When messing around with pen plotters a few years ago with a friend, we implemented an L-system driven plotter and one of the more interesting programs we found to run on it was an aperiodic Penrose tiling. We ended up throwing a party with the plotter going and art supplies so folks could grab a copy and color them in. Some videos below of the plotter in action.
https://www.instagram.com/p/Bfp0hATFzfm/?taken-by=dannysaza
https://www.instagram.com/p/BgS4MkeDEt0/?taken-by=dannysaza