This example shows one of the problems with this approach: Bob's car, which happens to be a sports car, is not able to carry and deliver construction materials (in any meaningful sense), but this is a capability that codice_1s are modelled to have. A more useful model arises from the use of subclassing to create specializations of codice_1; for example codice_7 and codice_8. Only objects of the class codice_8 need provide a mechanism to "deliver construction materials"; sports cars, which are ill-suited to that sort of work, need only "drive fast". However, this deeper model requires more insight during design, insight that may only come to light as problems arise.