@Guesswhoitis. Yep... well, I mostly study questions that are either obvious (and still unanswered), of personal interest, or clearly on the range where I can train myself on a problem that's relatively easy, but not entirely trivial (or hard). This was one I thought of being the sort I could reuse later myself.
Besides, so many thanks to meta users and other users for their helps and guidance. But I think, some decisions discourage new users. I think, if any user or new user knows where is his/her mistakes, he/she doesn't have to write their questions. Although, some questions seems to be too simple for...