Who is that "we" you're talking about? Because it's obvious that the parent does not "already know" and neither do many people.
People see trivial stuff like this simulation all the time, not knowing anything about the domain or past developments, and are inspired to learn more, or change it and adapt it to create something else, etc.
It would a sad world, yours, where everybody should delve in domain specific tomes to learn about prior art and theories and such, instead of also being able to give a quick glance at some web page and see something he didn't knew about.
Not to mention that "having been done before" and "it can be done in Javascript, on the browser, with adequate performance, and not that difficult code, and you know what, you can adapt it for your web project too" is a different thing altogether.