A tabletop role-playing game, also known as a pen-and-paper role-playing game, is a kind of role-playing game (RPG) in which the participants describe their characters' actions through speech and sometimes movements. Participants determine the actions of their characters based on their characterization, and the actions succeed or fail according to a set formal system of rules and guidelines, usually involving randomization. Within the rules, players have the freedom to improvise, and their choices shape the direction and outcome of the game.