I recently started playing around with the p5.js web editor and I created what I called the “Verlet Physics Playground”. That got me interested in other libraries in other languages that could be used for building real-time simulations like this. The rabbit hole I ended up in first took me to Common Lisp’s Sketch library. I love using Common Lisp and I’m especially enamoured with the interactive/REPL-driven development workflow. I had a lot of fun rebuilding the p5.