Fou refers to harmonic sounds produced by lightly touching the string with the left hand and plucking the string with the right hand.
(Fou; refers; to harmonic sounds) (harmonic sounds; produced; by lightly touching the string with the left hand and plucking the string with the right hand)
Fou harmonic sounds
refers produced
to harmonic sounds
by lightly touching the string with the left hand and plucking the string with the right hand