The sketch did not start. Browsers refuse to load ES modules from a file:// address, so this page needs a web server: it works as-is on the live site at https://arncademy.uk/Simulations/Automotive/FlexibleCarbody/index.html, or from a local server for the site folder, for example python3 -m http.server -d public 8000 from the repository root, then http://localhost:8000/Simulations/Automotive/FlexibleCarbody/index.html. If you are already on a server, check that p5.js reached the page from cdnjs and that the shared UI kit at ../shared/uikit.js is present.