Holden and Faylynn turn to face each other, sitting knee to knee. The rest of their classmates watch from their places in the circle. They touch their right thumbs together, wiggling their fingers like the wings of a butterfly. As they “fly” their butterfly in a circle, they greet each other. “Good morning, Holden!” “Good morning, Faylynn!”

Thinking is hard.

That is to say: real, active thinking is hard. Solving a problem or investigating a complex issue is the kind of thinking that requires complete focus - the kind of thinking that makes your brain hurt the same way your muscles do in a strenuous physical task.