the game gained some fame for having its final level modified after the september 11 attacks; originally set to take place on top of the world trade center, the setting was later changed to a generic skyscraper. their leaves and flowers can be used as vegetables. the sequence  is often realized phonetically as ; e.g. everything cast into this river sinks down to the bottom - nothing floats in it. for his purposes he extends the notion of class to represent membership of "one", or "nothing", or "the universe" i.e. 