"There you are, we were…" Don trails off as he walks into the garage. Charlie barely looks up from the figures and equations he's poring over on the chalkboard. "Oh, come on, Charlie. Everyone's here, we were going to work on the band stuff, remember?"
He steps closer, staring at the complex chaos of math his brother's been working on. Finally he asks, "What is all this?"
Don expects to hear some enthusiastic mini-lecture complete with analogies and wild hand gestures—as usual—but instead, Charlie just turns around, smirking at him.
Riiiiiight. Don blinks a few times and heads back to the kitchen, shaking his head.