…is, "Free"!so I have to pass along this news from The Aperiodical that back issues of a mathematical magazine, "iSquared" are now downloadable (pdfs) for free here:http://www.nationalstemcentre.org.uk/elibrary/collection/1860/isquared-magazine"Each magazine contains regular news items, a mathematical histories feature, puzzles, book reviews and the life of a great mathematician as well as spe