The piano is also considered a percussion instrument because the strings are set into motion or vibration by a hammer, which acts on the bridge of the piano, which cause the sounding board to vibrate.
(the strings; are set; into motion or vibration; by a hammer) (a hammer; acts; on the bridge of the piano) (the bridge of the piano; cause; the sounding board)
the strings a hammer the bridge of the piano
are set acts cause
into motion or vibration by a hammer
on the bridge of the piano
the sounding board