I love software prototype. Firstly, it can verify whether requirements can be implemented. Moreover, it can identify the most risky part of the systems and the programmers can acquire the skills raidly. For my personal projects, I was not sure whether .Net can searialize a List which contains a number of serialiable objects. So, I wrote a prototype which serialized a List which contains three serialiable objects into a 'test.dat'. Then that works. After that, I can write my little diary application.