A plagiarism scandal has erupted in the strange and esoteric community of crossword puzzle constructors, and — as plagiarism scandals usually do — it sheds some interesting light on what we mean by “plagiarism” and how that relates to what we mean by “copyright infringement.
https://www.washingtonpost.com/news/volokh-conspiracy/wp/2016/03/15/crosswords-and-copyright/