The Can of Ham cannot find a buyer. It may be hard to see the Gherkin because the Walkie-Talkie and the Cheesegrater get in the way. London’s skyline is made of glass, steel and nicknames. Sometimes these names start out as criticism: the city’s tallest building got its name when it was described as a “shard of glass through the heart of historic London” by a heritage group. But in time, they denote familiarity and, often, affection. On December 13th the City of London approved plans for a new skyscraper that will be as tall as the Shard; the chances are high that it will eventually wind up with a sobriquet based on its shape.