[Jefff8]

In answer to the the question posed on the linked page 'who's the author?', probably Anthony Edwards (https://en.wikipedia.org/wiki/A._W._F._Edwards) see https://quentinsf.com/software/venn/ and https://www.cambridge.org/core/journals/combinatorics-probab... and https://books.google.co.uk/books/about/Cogwheels_of_the_Mind...