Well the player is actually going through this experience of not just whatever storyline or set of challenges that you're placing in front of them, but there are also, again, kind of building this model. And the final model might be incredible complex and something they never accurately reverse-engineer, but you also want to ramp that model very very carefully. In some sense, of what you present and when you present it. // Magicians do this on purpose very well: they get you to build an incorrect model in your head with all these little hints that they provide to you, visual and otherwise, and at just the right time they break that model. And so you're convinced he has the glass under the handkerchief- he has the glass, he has the glass, and all of the sudden he pulls up the handkerchief and there's no glass. The correct model was that he actually palmed the glass back over here and that you saw this round thing under his fingers and you thought- so basically a magician is all about controlling the flow of information to you, such that they can break the model at just the right time, game design is similar in that we're controlling the flow of information to the player, and if we do it the right way, the player can actually build a very simple model that works, that's an improvement from what they came into the game with. From that to build up to a little bit more complex model, and from that a more complex model. And so that's a lot of what we want the player to be able to do in a game to feel satisfying. And then to keep this player in this sort of zone of challenge that's really satisfying that, again, they're failing frequently, but they always understand, "Oh I see. I didn't understand that one little aspect," and now they put another thing on the model, and now they want to go back out and play and try out their new model.