Description If you enjoy clambering around on rocks, you might enjoy bouldering. Find out all about this sport and how boulderers keep safe. The graphemes /y/ou/ are featured in this title.. . Bouldering is part of Decodables by Jump!, a comprehensive library of decodable leveled readers that follow a sequenced approach to phonics instruction. Young readers will enjoy colorful, photo-packed nonfiction as they follow a prescribed format supported by the science of reading that encourages reading development.