Indie style alert! Canadian alt rocker duo (and twins) Tegan and Sara share more than incredible musical talent—the sisters are also sporting the most talked-about haircut in the music industry! Since their debut in the mid ’90s, they’ve rocked everything from blunt bowls to Joan Jett mullets, but this latest look is their best yet. The TIGI team was on-hand to style hair at the South by Southwest Music Festival recently (where Tegan and Sara performed), so we asked TIGI Learning Lab Creative Director Mitchel Wilson to provide a technical breakdown of their cool coif. Here’s how he’d…