A few years ago Italian guitar virtuoso Marco Cappelli decided to chart, for himself, the state of music in downtown Manhattan, asking ten scenesters to compose for his extreme guitar—a six-string acoustic guitar retrofitted with ten sympathetic resonating strings. The collection of pieces, dubbed the Extreme Guitar Project, is as divergent as the group of old-schoolers that penned the sonic grab bag. One of the standouts on the disc sounds like a harebrained idea: a guitar piece for right hand only. Sure, there’s a tradition of left-handed piano compositions. This notwithstanding, Annie Gosfield’s Marked by a Hat is neither gimmicky nor, upon casual listening, revealing of its handicapped nature. In fact, the one-handedness only further focuses the piece’s exploration into unusual tunings and timbres. Cappelli proves to be adept both as performer and cartographer.