The Walls of the Universe (John Rayburn Universe") <1>

Tempted to trade places with a dishonest doppelgñger who steals his life and traps him in another universe with a broken travel device, Ohio farm boy John Rayburn inadvertently disrupts the balance of power by introducing the game of pinball, while on earth his look-alike attempts to sell the Rubik's cube for profit. 10,000 first printing.