I think it would be interesting to have a "swap" button between the start and end points, perhaps just under where it says "to". (similar to the swap buttons in translator apps and GPS apps to quickly swap the start and end points) As some other comments have mentioned, the paths are not necessarily the same route or length, and it is fun to see how they might be different.
Good suggestion! I intended to have that exact button, but couldn't find a way to put it in the UI without making things more confusing. I expect I'll add it in the future. Thanks for the suggestion!
