We have the basis of a toolkit for solving PDEs. The toolkit allows the addition of new components, which is necessary since the current set of components is rather simple. It also allows the addition of new ports and interfaces. The exercises should give you some confidence in your ability to modify the component code in order to perform new simulations. Further, the current set of components, especially Mesh and FieldVar are quite sophisticated and can be used in realistic parallel codes. However, in order to use them properly, one has to understand their usage in detail. This is described in Appendix C.