An excerpt from New Media Research Studio ( http://www.mushon.com/spr09/nmrs/04/11/reading-summaries/ ) by NA Young on Ralph Koster's lecture: "The Core of Fun"
"“Things that work have underlying structures to them.” You can see this in nature (e.g. the golden ratio), good art, good social media. We often use the term “grammar” to describe the thing that organizes and structures bits together. Grammars are fractal: you can keep breaking down whatever part you’re observing into smaller parts, finding structure at each level. Songs are made of smaller songs or overlapping smaller songs. Games are made out of smaller games. Take Frogger, for example: you have the game of getting a high score. To beat that game, you need to get your frog and fill all five of the spots at the other end. To win that, you need to get one frog to fill one spot on the other end. To win that, you need to cross the road and cross the logs, and to win that, you need to master hopping and timing, and so on, until you get to the interface button, which, hopefully, you can’t lose at (all you need to do is click). And for a game to be fun, it has to be fun at each of these levels. Fun is the act of mastering a problem mentally . . ."