Sometimes magazines come with bonus items inside, like pull-out posters or stickers. Nintendo Power magazine had these posters inside. Each poster has 2 sides. The Sonic Chronicles one has the (extremely detailed) art for the Green Hill Zone map you explore in the game on the other side and the Sonic Riders: Zero Gravity poster has another promotional picture featuring Sonic and Jet the Hawk in the transport tubes seen in the opening and closing CGI movies using Gravity Dive on hovercars.