"That was four sentences. Do you have any idea how much trouble Timothy could have saved me just by saying those four sentences."

"Demons and angels and fairies are indestructible, we haven't checked against the Killing Curse. They get summoned under bindings so they can't go around causing havoc. You're supposed to offer her something in exchange for the musical instrument and the complete musical works of the last four hundred years, if that's in fact what you wanted. Once you agree on a deal then she can make it for you."

"Four more useful sentences."

"I think that's it. Have fun."

He picks up a rock. He mutters something at the rock. It speeds off towards the building.

Minor trots off after it.

"...so you want a sphereflute? You still can't play it."

"I want every kind of musical instrument that was invented in the last four hundred years but the one you invented personally would be a really great start. Can you show me how it's played? I might be able to design a charm for it, if the problem is just that you have to be able to make nonmagical stuff."

She makes a Quaffle-sized ball in multicolored metal with holes in it. Music plays. She occasionally passes it from hand to hand, once when a particularly open chord plays she tosses it.

He looks utterly delighted and transfixed. "You're - making air for it?"

"Yup!"

"Darling brother, you," he says to his quill, "are forgiven for everything except wasting her time." Tap-paper-airplane. 

"That's amazing."

"It's not the first use of the idea, but it's one of the most compact and it's more fun than sitting at an organ or just cheating at bagpipes." Toss, catch.

Awestruck contentment. 

"- I'd need a hand free to cast but it's probably not totally impossible, let me think what I can come up with. Who wrote the song -"

"Me. First song I wrote for sphereflute."

"It's beautiful. Do you mind if I sing along?"

"...you don't know the tune and it doesn't have lyrics."

"I have been listening to the tune for the last few minutes and am really good at that in particular and don't have to sing words."

"Knock yourself out then."

He totally will! 

He in fact has a pretty astonishing singing voice.

Pretty soon she is grinning as she tosses her flute around.

Oh, good! He watches it and tries to learn the fingerings and sings along.

It's not so much fingerings as palmings. The colors seem to be meaningful; it would otherwise be hard to tell the holes apart. There are probably several disconnected cavities inside.

His brother has excellent judgment after all. He is - not exactly surprised. He starts trying to mentally map out the cavities.

The song comes to an end; it was a cute little etude, probably as much proof of concept as anything else.

"Thank you very much. That was lovely."