Part 191: (Eva's Hint)

"No, I'm stuck."
"See, even Ange-chan says she's stuck! Give her at least a little hint."
"I, I see. Then, a hint... They may be different colors, but you get a beautiful sound no matter which you push."
"A beautiful sound...? Are these black and white things something that make sounds?"
"Black and white things that make a sound when you push them...?"