I'd pick #2. Suppose that we know that we must move. Implicit in move is how far, how fast, when to start, when to stop, and maximum speed. Suppose the task of move() was to calculate some missing value in the above properties. Appropriate formulae can be placed in the move method to perform calculations. Subclasses of such an item would alter the formulae (polymorph the method) and use the same property settings (inherit properties) or inherit the method and alter the property settings. Since Fly(), Drive() or Row() all must change or use all the properties listed, there would be no need for them idividually we would just use move(). If different formulae were called for to Fly(), Drive(), or Row(), We would alter the method in the subclass but still use the same properties and we might still be able to use some of the code already present in the superclass.