User interfaces are hardly limited to personal computers: even by a restrictive definition, they're ubiquitous around us from ballpoint pens to stick shifts. Here, for instance, are some user interfaces for generating music through the vibration of strings: ... and here, for turning the motion of air to a like purpose: ... and here, an interface common (to an extent) to both: It has ever been the business of music to avail itself of new technologies. Small wonder that many such start from the familiar means to generate music, and the familiar interfaces: But technology can also open unthought-of new channels for a person to relate to his or her creative output ... and entire new ways to create. For instance, the omnichord: ... the theremin: ... and the reacTable: