I assume this works the same as pythontutor.com by executing a code snippet through a debugger and playing back the execution trace. Is each code snippet custom created, or do you have a tool that generates these visuals?
This is opinionated custom visualization, and I do not have some generic tool here. I think it is possible to do it, but it will be
* generic, like pythontutor - it misses "meaning" of what's happening, just showing the facts without emphasis
* specific cases for popular data structures (I thinking about that way)
* hand-made every time (like a Disney in old good times) - hard work =)
I'm just scratched my own itch, and learned vue.js + vuex + a bit of modern frontend during this project.