This paper describes the technologies, collaborative processes, and artistic intents of the musical composition Engravings for Prepared Snare Drum, iPad, and Computer, which was composed by Timothy Polashek for percussionist Brad Meyer using a jointly created electroacoustic and interactive musical instrument. During performance, the percussionist equally manipulates and expresses through two surfaces, an iPad displaying an interactive touch screen and a snare drum augmented with various foreign objects, including a contact microphone adhered to the drumhead’s surface. A computer program created for this composition runs on a laptop computer in front of the percussionist. The software captures sound from the contact microphone and transforms this sound through audio signal processing controlled by the performer’s gestures on the iPad. The computer screen displays an animated graphic score, as well as the current states of iPad controls and audio signal processing, for the performer. Many compositional and technological approaches used in this project pay tribute to composer John Cage, since the premiere performance of Engravings for Prepared Snare Drum, iPad, and Computer took place in 2012, the centennial celebration of Cage’s birth year.