I like to always start with YAGNI, and then try some of these exercises after I already have something that kind of works - its much easier imho to refactor som

I like to always start with YAGNI, and then try some of these exercises after I already have something that kind of works - its much easier imho to refactor something that is simple and gets the job done, i.e. add-to versus something that is wrought with way too many abstractions and such.