I then gave our dear friend Johann Heidenberg an official journal's biography. The hint that his book (one he actually wrote!) was written in 1508 should give some clues to my colleagues as well. I also decided to be bold and mention that he is interested in cryptology as well :-) Just a tiny clue! And it can't be seen on any of the pictures, but I gave the first page of the story the page number 707. Upside down this spells LOL - an acronym for laughing out loud, of course. But it also means "fun" in Dutch.