I was cross …
… with my provider. Friday late afternoon I noticed that my site returned "Forbidden. You don't have permission to access xx on this server.". I checked everything from my side: ftp access was fine, files had the correct permissions, there was not htaccess… So I notified my provider, got a canned response. Next morning still down, phoned them: no service over the weekend. Grrrr, as we say in Germany.
So this weekend you can't enjoy my lovely visual phenomena & illusions… ;-) The movie below is a poor substitute.
Addition: very early Monday morning my provider fixed the problem and sent an apology. Ok.