Dedicated “to children everywhere sitting in cardboard boxes,” this elemental debut depicts a bunny with big, looping ears demonstrating to a rather thick, unseen questioner (“Are you still standing around in that box?”) that what might look like an ordinary carton is actually a race car, a mountain, a burning building, a spaceship or anything else the imagination might dream up. Portis pairs each question and increasingly emphatic response with a playscape of Crockett Johnson–style simplicity, digitally drawn with single red and black lines against generally pale color fields. Appropriately bound in brown paper, this makes its profound point more directly than such like-themed tales as Marisabina Russo’s Big Brown Box (2000) or Dana Kessimakis Smith’s Brave Spaceboy (2005). (Picture book. 5-7)