The thought processes (theory) necessary for the designing of such challenging amusements as mazes, other board, card, computer games, slot machines, etc. A game consists on rules defining a gaming environment, and the potential action of players within it. Rules place requirements on what become the objectives of the players, ultimately determining success ? differentiating winners and losers ? further depending upon variable degrees of chance and skill. Considerations fundamental to the design of a game is its potential degree of difficulty (or "targeted age-group"), number of players, expense, and duration of play.Games have been important in the visual arts for the kinds of imagery needed to create the gaming environment, and to entertain players and spectators. A great many American artists of many kinds have been employed in the last few years by the recent expansion of the electronic and casino gaming industries. Income from such games has far surpassed that derived generated by many otherwise huge industries. Currently, slot machines are earning more profits "than McDonald's, Wendy's, Burger King and Starbucks combined. All told, North American casinos took in $30 billion from slots in 2003 ? an amount that dwarfs the $9 billion in tickets sold in North American movie theaters that year." (NY Times Magazine, May 9, 2004, p. 44.)"Game theory" is also a mathematical method of decision-making in which a competitive situation is analyzed to determine the optimal course of action for an interested party. This is also used in political, economic, and military studies.Some examples of games imagery:American, McLouglin Brothers, Round the World: Nellie Bly, A Novel and Fascinating Game, 1890. This game commemorates the achievement of Nellie Bly, who traveled around the world in 72 days in the late 1880s. Jules Verne, the pioneering French science fiction writer, retold the story as Around the World in 80 Days.German, Ariston, Backgammon Game for computer use, 2000, screenshot. Backgammon has a history going back to ancient Persia, China, and Rome, with boards having been made of simple slats of wood nailed to a plank, magnificent inlaid tables of ivory and rare woods, or ebony and mother-of-pearl.Japanese, Nintendo, Tomb Raider for Game Boy Color, 2002, cover on packaging. Electronic games have overtaken all other types of games in popularity. They engage players both as passive viewers, and, to varying degrees, allow players to actively manipulate their imagery. Electronic games have become a huge industry too. See anime.Other resources about game theory: Because an American economist called his Nobel-Prize-winning theory "game theory," some people think economists have a corner on the use and meaning of this term. The economic version of game theory is nevertheless strongly related to ArtLex's broader definition. Also see avatar, chess, effort, exquisite corpse, motivation, success, and visual culture.