[ Yu's never great at showing wide ranges of emotion, but really, he's incredibly pleased, subtle though it is. This is the edge they needed in making real progress. To finally have a way to make plans that CERES couldn't hear and can't have access to... this is it. He remembers discussing it with Dipper months ago. His best idea was Braille, which was wildly impractical. This is leaps and bounds better.

Senpai Has Noticed You, Hiro. ]

No wonder you couldn't tell me. This is what you two have been up to this whole time? [ There's the traces of a disbelieving laugh in his tone. ] You know, this makes it even easier for me to tell you what I was coming over to talk to you about.