as a graph of a unmusical machine is plucked harder , the elements will vibrate harder / faster
tapping is not sound. voilin is not stringed_instrument. sound_clip is tangible_thing. tapping is sound. one_kind_of_musical_instrument is not hurdy_gurdy. clipboard is mechanical_device. plethysmograph is not measuring_instrument. clipboard is not mechanical_device. sound is mechanical_vibrations. sound is not mechanical_vibrations.