I understand your want to complete a project using object oriented concept, but I think it would be far more beneficial to you if you to do smaller projects, learn proper object oriented design then do a larger project.

And there is no solid definition of a large project, especially with lone programmers. I consider large projects (when I am alone) anything over 1,500 lines, but I am used to programming large applications (the ASP one I maintain is about 100k lines). Back when I was a newer programmer, large was over a few hundred lines. A blog would certainly run into this, so I wouldn't consider it a small project for you.

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