I can barely imagine a more fitting love sonnet for good old (modern) C99/11. My eyes, dear $deity my eyes. I'm sure OP is a fantastic(ally) smart dev but I'm kind of glad I don't have to work with that.
Eigen is a quintessential example. It's some of the most complex and inscrutable template code out there but it makes writing numerical code in C++ almost as nice as matlab while also being extremely fast.
Want to look at some tasteful C++ code? Check out LLVM.
http://isocpp.org/files/papers/N3949.pdf
Behind that wonderful STL code lies some crazy code behind the scenes. Is it beautiful? You won't catch me taking that argument! But is it typesafe with minimal overhead and easy for the end user of the code to understand and use? That's the one that's most important. For all the complexity of the template function itself, using it comes down to this:
auto window = sdl2::make_window("App Name", SDL_WINDOWPOS_UNDEFINED, SDL_WINDOWPOS_UNDEFINED, 640, 480, 0);