tokens) must move to score game points. Worker placement Worker placement is a game mechanism where players allocate a limited number of tokens ("workers") to multiple stations that provide various defined actions. The worker placement mechanism originates with board games. Stewart Woods identifies Keydom (1998; later remade and updated as Aladdin's Dragons) as the first game to implement the mechanic. Worker placement was popularized by Caylus (2005) and became a staple of the Eurogame genre in the wake of the game's success. Other popular board games that use this mechanism include Stone Age and Agricola. Although the mechanism is chiefly associated with board games, the worker placement concept has been used in analysis of other game types. For instance, Adams and Dormans describe the assigning of tasks to SCV units in the real-time strategy game StarCraft as an example of the worker placement mechanic. Game modes A game mode is a distinct configuration that varies gameplay and affects how other game mechanics behave. A game with several modes will present different settings in each one, changing how a particular element of the game is played. One of the most common examples of game mode is the single-player versus multiplayer choice in video games, where multiplayer can further be cooperative or competitive. Common game modes include a Time Attack Mode, in which the player tries to score, progress or clear levels in a limited amount of time. In Marathon Mode the goal is to clear a certain number of levels or challenges in a continuous streak without losing. Changing modes while the game is ongoing can be used as a means to increase difficulty and provide additional challenge, or as a reward for player success. Power-ups are modes that last for a few moments or that change only one or a few game rules; for example power pellets in Pac-Man give the temporary ability to eat the enemies for a few seconds. Other examples include the availability of a sandbox mode without predefined goals or progression. The division of game content in stages or chapters, where each stage expands the rules that a player can use with respect to the previous stage, increases game complexity, and variety. If the game advances through these stages by moving through different areas, these areas are called levels or maps; if the character unlocks new abilities through activities or rewards, they receive a currency called