Rodolphe Bourotte / The Centre Iannis Xenakis has released UPISketch, a free app for iOS that can run on iPhones or iPads from iOS 9.3.
UPISketch is a sound composition tool, which is based on drawing: the user can sketch and design sound gestures, from existing sounds, by redefining their melodic contour, as in the case of a conventional score. Pitches are, nevertheless, drawn directly at specific time points, without requiring any knowledge of solfege.
UPISketch is intended to be simple and intuitive.
Price: Free in the App Store.