Mail Duck is delivering differently shaped packages to all his friends on his mail route. (Trudy likes triangles, and Harry likes hearts ) Lift the flaps to peek inside and guess what each friend received. Then head back to the post office for a big surprise: a thank-you celebration for Mail Duck planned by all his pals using the various packages they received throughout the story Sixteen flaps and a final double-gatefold spread give readers plenty of sweet and silly details to unpack in this charming board book.