A four-piece band of 20-somethings won a Battle of the Bands in Pittsburgh this month, thrilling the audience with their up-tempo, energetic performance and enthusiastic devotion to rocking out. Nothing unusual about that, right? Well, in this case, the four performers were all classically trained cellists, the band is called Cellofourte, and the songs they play are “energetic instrumentals that sounded like a mix of Vivaldi baroque and speed metal.”