喻教于乐,通俗易懂.
Design Your Soccer Engine, and Learn How To Apply Design Patterns (Observer, Decorator, Strategy and Builder Patterns) - Part I and II
http://www.codeproject.com/useritems/applyingpatterns.asp
Design Your Soccer Engine, and Learn How To Apply Design Patterns (Observer, Decorator, Strategy and Builder Patterns) - Part III and IV
http://www.codeproject.com/useritems/applyingpatterns2.asp