“Everyone should make a short,” advises writer-director Sherman Alexie (“Smoke Signals,” “The Business of Fancy Dancing”). “It’s a great lesson in the economy of ideas.” His five-minute docu “49” was commissioned by the Seattle Film Festival as part of a filmmaking challenge. Alexie and nine other local Seattle filmmakers made brief, digital docus (between three and five minutes) based on a word randomly chosen out of a hat. Alexie drew “music.” Pic is his humorous take on the evolving Indian music form, which combines traditional drums and vocals with modern pop tunes. Alexie says the short, shot and edited in 10 days, was a communal effort.