! is here used not as a punctuation mark but as a phonetic symbol for the alveopalatal click produced by pulling the tongue sharply away from the front of the hard palate - the classic sound made to imitate horses’ hooves. (People who can't make this sound may substitute the lateral, or fricative - phonetically: || click. This is the 'gee-up' click made to encourage horses.)
This is a resonant title in more ways than one: it reflects not only the abstract and percussive qualities of the piece, but its mouth resonance reflects the rich superimposition of horizontal layers sometimes to be found in the piece. Furthermore there is the occasional inspiration of the antiphony, polyphony,and hocketing of flutes, mouthbows (more mouth resonance) mbiras and singing of those peoples that use such click sounds in their language.
© Benedict Mason, reproduced with permission of Music Sales Ltd.