So often one item comes to symbolise an entire protest movement. In China, that item is a humble piece of blank paper. As dusk fell on Shanghai on Sunday evening, some of those who gathered at a vigil to remember the victims of a fire that catalysed the demonstrations came clutching sheets of paper. Similarly, in the capital Beijing, protesters came armed with scraps of paper to a demonstration at Beijing's prestigious Tsinghua University, once attended by President Xi Jinping. And in an...