Show HN: Five-couples-meet problem, visual guide to solution

I found this problem in Scientific American in the 70's, and it's been one of my favourites since then. It is possible to solve it without even using pen and paper (I believe I did back then), but I got the idea that some visual guidance could be helping to some. That's why I made this little single-file web "app". (You may add "?lang=no" to the URL to get Norwegian texts.) Have fun!