Chinese artists Ai WeiWei missed the opening of his big exhibtion in the Photography Museum in Winterthur, Switzerland last year because he had been disappeared by Chinese secret police. Now released, he still suffers from major harassment at the hands of the authorities. This has not stopped him from being involved in the current exhibtion in Zurich called Art and the City. As part of this urban exhibtion Ai's White Armchairs have been installed on the Paradeplatz, the financial heart of Swiss capitalism. The chairs stand outside the headquarters of Credit Suisse and the UBS banks. They look comfortable, but are made of very hard marble, a material popular among the rich elite in "communist" China today. The piece seems to be called White Sofa, but these are armchairs, not sofas, or have I got that wrong?