Players are encouraged to contribute participatory content to the game, whether as coders, artists, plotters of events, or as special staff-directed characters, known as "Veteran Players," which are akin to cast actors in a play. Plots remain open-ended; though there are often ostensible goals for the players to achieve and long-term plot arcs, there are not pre-scripted outcomes to many interactions (known as "scenes") or to whole stories, making the social evolution of the game partly in the staff's hands, and often in the control of the players themselves.