Cataloging several examples for each of ten regular shapes, Greene develops in an ever-changing rhyme scheme the premise that all shapes are made from bent lines. It's an eye-opening insight for readers, but confusing when blocks are considered square, a bubble, marble, and ""curled kitten"" are included in the list of circles, and ""star"" is defined as ""the shape of a fish."" Readers may also falter at the triangle spread, since the three blocks of text are placed so that it's hard to tell in what order they're to be read; the ""tent built just for you"" has a triangular opening, but what children will notice is the diamond-shaped side. Kaczman's picture-book debut features a set of stylized, evenly colored, very simply drawn scenes, sometimes viewed from playfully skewed angles or featuring sight gags--a police officer chowing down on a doughnut, a kilted man playing hopscotch. Still, an instructional intent hangs heavy over this, and the examples are not always on target; a better book on the topic is Dayle Ann Dodds's The Shape of Things (1994).