"That's what I thought! Obviously! I spent the first fifteen minutes trying to get her to explain what the trick was, until I realized it wasn't working. And then we tried to explain each other's languages to each other, until suddenly she..."

He turns to Sohng. "I'm going to have her show you the thing."

He hands Sohng a small piece of white blackboard chalk, and a large piece of red sidewalk chalk. He mimes the two-handed shaking gesture.