Pinch to draw. Move an open palm to rotate.
Turn your drawing into music.
Start with one hand: pinch to draw, release, then move an open palm to turn the view. You can take turns drawing and rotating. Try both hands together when you feel comfortable.
Mouse: drag to draw, right-drag to orbit, scroll to zoom. B / E / O switch tools; Ctrl/⌘ Z undoes.
Depth is estimated from a regular camera. Keep both hands well lit and visible; avoid crossing them.