Mischievous Triangle lives in a triangular world where everything fits just right. When he ventures out into the world and finds other shapes, he decides to play a sneaky trick on Square. Knowing Square’s fear of snakes, he hisses right at the square-shaped door of his square-shaped home, and when Square realizes he’s been fooled, he chases Triangle back into his triangular world, and gets stuck in Triangle’s door. But the joke turns out to be on Triangle because guess who’s scared of the dark? Klassen’s illustrations manage to give a lot of character to geometrical shapes with minimal details, and they add greatly to the humor of this witty story. (Ages 4-7)