In a film packed with great costume and set design (Leia's buns! The AT-ATs! Tauntaun guts!), the Stormtroopers' glistening white exoskeletons are among the most memorable details from Star Wars. Which is what makes Art Wars a lot of fun: As part of a show at London mega-gallery Saatchi, 19 artists were given a trooper helmet and told to go wild.