Who invented the gravikord?
Correct answer: Robert Grawi

Chelseablue 1971
ChewyGazelle68623, I thought pictured was a Honda 50cc exhaust system! gulp

Lunarsea
Presumably the name of it comes from "grawi"

aqualung
Check out the wind harp...amazing

Player #25874027
Chelseablue 1971,
Slightly more tuneful.