Show Hide image 4 July 2012 Chart of the day: Venn diagrams 101 for Mitt Romney Poor old Mittens. He went to all the trouble of producing a fancy infographic, and it makes no sense. Won't somebody give him a run-down on how Venn diagrams work? By Alex Hern Alex Hern is a technology reporter for the Guardian. He was formerly staff writer at the New Statesman. You should follow Alex on Twitter.