In Blake Nelson’s new film “Leaves of Grass,” Edward Norton plays two characters (acting win): Brady, a Brown professor from Oklahoma and his pot-grower stoner twin, Bill. Think “Weeds” meets “life at Brown.” Er, just think “life at Brown.” While we’re not sure that Walt Whitman would be entirely pleased with this arrangement, we’re intrigued. Ever thought that one of your professors had a secret double identity as Sherlock-Holmes-the-pot-brother-investigator? Look up at your professor. Now look back at the blog page. Don’t try to tell us you didn’t just see it a little bit.