Rui has a hyperfixation.

Now, this isn't bad on it's own. But...it's really interfering with everything else now. He can't think of any new show ideas, any new machines, nothing.

This one invention has just...taken over his life temporarily. The worst part is that it's making conversations difficult; it's difficult to sit through any conversation topic that isn't about robotics. Like, overstimulation difficult. He needs to talk about his robotics before he explodes.

Oh god, he hopes that it isn't obvious that Rui doesn't want to talk about whatever Tsukasa is droning on about. Yes, he's being polite about it, but Tsukasa will notice eventually, won't he?