A single page web app inspired by Bret Victor's talk "Inventing on Principle".
Talk: https://www.youtube.com/watch?v=PUv66718DII
In the talk, Bret Victor demonstrates a Mario style game in JavaScript with a time travel debugger. He can pause the game, scrub back and forth through time, see trails of the character's past and future, and change values in the code to see how the future changes.
This project recreates that demo in a single HTML file: time-travel-debugger.html. Open it in any browser. There are no dependencies and no build step.