How about giving players as much ownership and control in the game as possible, but without requiring hard-coding? How about software that reacts to the player's decisions on its own instead of having instructions preprogrammed?
Now, suddenly, his creature could walk. And he did so -- he walked right out of the sea and onto the land. This incredible moment in the history of evolution was made even more remarkable by the technology behind it: the game had figured out, procedurally, how a creature would walk if it had three legs (it was a kind of lopsided gait, if you're curious, with three steps: left, right, then middle.) No 3D modeler created the creature, and no 3D animator was required to make it move around -- it was all created out of a gamer's whim and a computer program smart enough to make it work.
Will Wright Presents Spore... and a New Way to Think About Games