We agree it is simple, but actually, it isn’t so much Python per se, it is some pretty cool libraries (SciPy, in particular) that do all the hard work.

It's possible to take a step further with a browser extension, but this is a basic Python project that hosts a web page that you can drag and drop a file on for a visualizer.

The output of the simulation is a numpy array, which can be further processed and visualized with the mathplotlib library. All pretty standard stuff in python circles.