Plasma Sound is the most fully-featured and 100% free music instrument on the Android Marketplace! Beautiful music instrument inspired by the Theremin, Continuum, Keyboard and Sequencer. Touch the screen and a note is generated. It's X-Axis (left-to-right) is pitch, which is designated by note and octave markings. It's Y-Axis (up-and-down) is up to you to control!