For the most part, I would expect photography classes to focus (ha, get it?) primarily on making a clear, crisp image of your subject. I could be wrong, but that's the impression that I get.
But hey, if all pics out there were as clear as possible, it would be a bit boring, wouldn't it? We want a bit of fun challenge from time to time, don't we? Well, here are some pics that provided a good head-scratching.