Description No Nap for Zack . Zack wants to take a nap, but noises stop him. He has to fix them before going back to sleep. Zack Gets Zapped . Zack and Max love playing Zipzap. But when Zack gets sucked into the game, can Max get him out? The phonemes /x/y/z/zz/ are featured in this title. In Level 3 - Yellow books, children build on the letter-sound combinations learned in levels 1 and 2. They learn consonant digraphs (sounds made up of two letters together such as 'ch' or "ll") and long vowel sounds (such as 'igh' or 'ai').