The app is part of Paul's Walk, an interactive musical/text work for performer(s) and iOS app.
Visit http://www.novamara.com/pauls-walk/ for more information and to obtain the music score and other materials. This is the visual text animation with live audio processing. You can try it out without the full set up - you need to wear headphones to avoid feedback. Click the info button on bottom right of App screen to find out more, touch lower screen to start and make sounds (sing or play).