text:  With a satisfying protagonist completed , Sega turned to esteemed programmer Yuji Naka , who had impressed them through his work on Phantasy Star and the Genesis port of <unk> ' n Ghosts . The gameplay originated with a tech demo by Naka , who developed an algorithm allowing a sprite to move smoothly on a curve by determining its position with a dot matrix . Naka 's prototype was a platform game with a fast @-@ moving character rolling in a ball through a long , winding tube , and this concept was fleshed out with Ohshima 's character designs and levels by designer Hirokazu Yasuhara . Yasuhara originally intended to work on the game for three months due to the delay of his planned move to the United States by the outbreak of the Gulf War , but was engrossed in the project for nearly a year . His designs for levels were intended to attract both hardcore and casual gamers by integrating occasional challenging set pieces into the mostly accessible level design . The game 's color scheme was influenced by the work of pop artist <unk> Suzuki , and the aesthetics of Green Hill were influenced by the geography of California . 
  