usually designed to get players to explore the mechanics of the game, notably in World 1-1 of Super Mario Bros. Cut scenes may be triggered by events in a level, but require distinctly different skills, and may be produced by a different person or team. The level design process may be iterated several times before achieving the desired outcome. Level designers and concept artists may also be required to provide a pre-rendered map of the level (or entire game world) for the player. Design goals Level design is necessary for two primary purposes: providing players with a goal and providing players with enjoyable play experience. Good level design strives to produce quality gameplay, provide an immersive experience, and sometimes, especially in story-based games, to advance the storyline. Skilled use of textures and audio is necessary to produce immersive player experience. Player directing Levels are generally constructed with flow control in mind; that is, directing the player towards the goal of the level and preventing confusion and idling. This can be accomplished by various means. Often the level layouts feature power-ups and items positioned so that collecting them inevitably makes the player move in the correct direction. This is one of the basic player direction techniques and is most often seen in platformers. Lighting and illumination, as well as distinctly-coloured objects, are often used to unambiguously guide the player towards the correct path. Similarly, clearly marked choke-points can be introduced. Another method is strategic placement of obstacles and aesthetic environment props that direct the player's attention to "clear" paths instead. This is often used in closed, "stuffed" environments. Levels may be designed to force the players to explore the map and advance. Most Real-Time Strategy maps give each player a starting base, but will have resource distribution and terrain features designed to draw players out of their base and engage each other. Teamplay maps can provide noticeable advantages to one team over another, when designed poorly. Level streaming Common on older hardware, most games would load a single level and all of its assets at one time, and when the player completed the level, the next level would be loaded. The player would be presented with a loading screen while the game loaded level information from storage. With more advanced computing hardware with faster input/output data transfer rates, such as optical drives, hard disk drives (HDDs), solid-state drives (SSDs), and larger