Inheritance relationships are usually displayed graphically in a tree diagram (see Figure 7.1).
Figure 7.1. Car tree diagram.
Figure 7.1 shows that the root of all the classes, or the top-level super class, is Car. The Car has three subclasses: Porsche, Pinto, and Corvette. In this tree, the Pinto and Corvette do not have any subclasses and are referred to as leafs of the tree. The Porsche has two subclasses: 911 and 944. To these subclasses, the Porsche is the super class thus, the Porsche is a subclass of Car and a super class to 911 and 944. Finally, the TwinTurbo class is a subclass of 911.
These diagrams will greatly help you understand the relationships between your classes.