It's probably worth adding a css cursor rule so users can tell that things can be dragged when they mouse over. That said: I'd love to see the more detailed exp

It's probably worth adding a css cursor rule so users can tell that things can be dragged when they mouse over. That said: I'd love to see the more detailed explanation that guides your algorithm. Because auto-curvature is always useful (ever since Knuth wrote down metafont ;)