Every 4 years a new Olympic art portfolio is produced. This time 12 British artists came up with some stunning editions: Bridget Riley, Rose Rose (picture). Tracey Emin, Birds 2012. Anthea Hamilton, Divers. Chris Ofili, For the Unknown Runner. Howard Hodgkin, Swimming. Martin Creed, Work No. 1273. Rachel Whiteread, LOndOn 2O12.Michael Craig-Martin, GO. Gary Hume, Capital. Bob and Roberta Smith, Love. Fiona Banner, Superhuman Nude. Sarah Morris, Big Ben 2012.