Nice, but it's only available in English sadly, there's a link that says "see kalenderpuzzel "Ruit" for the Dutch version" (I'd prefer French but Dutch would do as well) but that page says "De maanden en dagen van de week zijn in het Engels".

The "square" one is in Dutch but sold out and the Rotterdam one in English only.

But I like that idea, apparently it's not the first puzzle of this kind but I didn't know about them.