The berimbau, a one-stringed musical instrument that looks like a bow from a bow-and-arrow, is customarily strung with the wire found within a car tire. When Afro-Brazilian percussionist Nan Vasconcelos set out to build his own, however, he strung it instead with a single Steinway piano string, signaling his desire to take the instrument beyond its traditional settings. Nan grew up in Northeast Brazil, surrounded by the resourceful improvisation...