Oh--those are new, and maybe they'll even be a problem--obviously, Frisk knows which side has which sound on the entire keyboard, but they almost never use the black keys on their own, outside of the one they play for Serif. (Mostly because their fingers are a little too short when they're playing actual songs.)

Not yet, though. The novelty of it's enough to get them to match after a pause, add those three.

As well as words--wait, no, it's not a part of the game itself, just a comment, a whisper with a smile at the keys. "Guess we're making a song together anyway."

And two more, tapping black keys furthest to the right.