>So you're saying that you create several different classes with the same methods and properties (but the source or values in those PEMs may be different) and then create an instance of the applicable object?

That's right. Typically, you'd define an abstract superclass that encompasses the range of strategies for a given purpose (such as sorting), define concrete subclasses for each particular strategy (e.g., bubble sort, quicksort), and let clients instantiate whichever one is most appropriate at runtime. (I could give a better example if I knew what the original questioner's needs were).

It's in "Design Patterns."