Circle is playing hide and seek with her friends Triangle and Square and insists no one hide in the cave behind the waterfall—she’s afraid of the dark. Still, she goes inside when it’s clear that’s where Triangle must be. The deeper into the cave Circle goes, the darker it gets, until only her eyes are visible. When a second pair of eyes appear in front of her, she voices her frustration at Triangle, then apologizes: “You are a good friend.” A third pair of eyes appear behind her. “Thanks!” says Triangle. In a picture book full of humor, but also a little tenderness and a big surprise, the expressive eyes in the muted digital, graphite, and watercolor illustrations speak volumes. Reunited outside the cave, the three shapes imagine what other shape might be inside the cave; the book’s open ending invites children to do the same in this companion to Triangle and Square. (Ages 3–8)