Rules are one of the hallmarks of civilisation and, in a civilised society, most people abide by them. Rules, after all, are our invisible prophylactic against chaos. Except that rules are not always invisible – they also take physical form. Roads and pavements are rules, keeping hard cars and soft pedestrians apart. Lane markings, pedestrian crossings and steel railings are another layer of rules. Do we really need such nannying? What if we relaxed the rules a little?