a group of talking (or listening) pieces of fruit in a cave...
"be still a minute - isn't that a piano playing?" asked connie cranberry.
"it does sound something like a piano," added clara current.
"and so it is, except that it isn't the kind of piano you are thinking of," said moon queen. "jolly jim calls it the 'pebble piano', because each of the keys are made of rock. he is playing upon it now by striking the different rocks with his walking stick. as each rock makes a different tone, he is able to play any tune that he wishes to try."
"ho! ho! you didn't know that i could play the piano, did you?" chuckled jolly jim, after he had rejoined the party. "but i want you also to know that pebble piano can play much louder if a large hammer is used for striking the rocks..."
(from brainy berries - a night in crystal cave, by t.b. faucett, 1924)