Of course, usually you'd need several classes before any common features will appear. But because I've already thought this example through, you can cheat a little. Therefore, you can create a more general class than Pen. Figure 14.2 shows this new class. Figure 14.3 shows how the two classes are now related.
Inheritance is really no more complicated than that.
The child class has the properties of itself plus whatever the parent class has. You haven't seen methods or functions used in classes yet. This was deliberate. Methods are inherited in the same way that data is. However, there are a couple of tricky aspects of using methods that are better left for later.