Read the excerpt from "Object Lesson, Part 2."The 41 boys and girls were buzzing and giggling now.Ellery pounced. Clinging to one of the rectangles was a needle-thin sliver of paper about an inch long, a sort of paper shaving. He fingered it, held it up to the light. It was not newsprint. Too full-bodied, too tough-textured . . .Then he knew what it must be.Less than two minutes left.