Classes and external code packages are used for simplifying an application once your applications get so complex that they will need it. It is my opinion that one should begin creating complex applications on the timeline directly, then move to external class coding. If you want to argue with me then go ahead... This video was made because so many people like timeline coding... and big dorks want them to not do that. You can disassemle any package and class code that you find online with little effort if you like coding complex apps in the flash timeline and keyframes in the actions panel. Maybe one day I will change my mind on this matter regarding Flash programming, but I understand how and why to create custom dynamic classes in Flash ActionScript 3.0 fully, and prefer not to unless there is a strong need to.