OPEN WIDE Two accordion books--Rain Forest: A Fold-Out Book by Nicholas Harris, illus. by Colin Woolf, and Oceans: A Fold-Out Book by Harris, illus. by Peter David Scott and Eric Robson--capitalize upon a spacious format to represent their expansive subjects. The books open out into continuous five-foot illustrations, one side vertical and the other horizontal, both drawn to scale. Brief entries identify the featured wildlife.