Articles by Michael Kielstra Michael KielstraMichael Kielstra goes by many names. As 13Clocks, he has written a number of websites and Android apps. As the Wandering Mathematician, he maintains a weekly mathematical blog. As himself, he is a student in England and an avid reader of Chalkdust.All articles by Michael The mathematical con artist11 January 2018Some summations seem strangely slippery...