The Chinese artist and activist Ai Weiwei currently has an exhibition on Alcatraz, the notorious island used as a military fortress and federal penitentiary. Amongst a large body of work created specifically for Alcatraz is “Blossom,” which has been installed in several hospital ward cells and medical offices. And as its name suggests, intricately detailed encrustations of ceramic flowers are blossoming out of sinks, toilets and tubs that were once used by hospitalized prisoners.