The Lost Bay Software Coop purchased EnviroMeasurements, a small startup with a product, GreenStation, that measures pollen count and air quality. The company has ventured into the realm of manufacturing by producing a hybrid measurement station. The Redwood Bay Weather Association is definitely interested in replacing its aging collection of WeatherStations, but what they don''t want is to change the software. The Association, now renamed Redwood Bay Environmental Society, wants to add the pollen count and the air quality index measures, but doesn''t want to change the interface. Everyone agrees, but Captain Jack is pondering a complete rewrite of the system when Hobo Mary, recently promoted to Chief of Design--or as she likes to call it, Head Crackpot--declares in no uncertain terms "Piece of Cake. We''ll take the existing class, GreenStation, use it as a base class and derive the WeatherStation class from it!