Spacey Theremin Instruments app.
Touch&move screen will change pitch.

pro version is no ad and You can use with no limit additional tools in the future.
Multi-touch free2 pro10

View menu by Shake

at menu->setting
Delay
On/Off
Time
Feedback
Wave
Sine
Saw
Square
Triangle
Noise
Warp On/Off
Softness
Volume

Features will be added:
Control by sensor like rjdj.
and more...

Recommended for those who like:
Bloom Music Sampler keyboards piano guitar bass drum sequencer Psychedelic Media Arts Reactable Loop Theremini Animoog