Recently I've been re-reading books I read when I was younger, and there's one that I just cannot remember. This was about a decade or so ago, so I would have been about 10 (plus or minus a few years), which might help determine the book. I'm not sure how long it was, but I assume it wasn't more than a few hundred pages, if that.

The only thing I really remember from it is this 'riddle':

Earth, Water, Fire, Air

Met together in a garden fair

Put in a basket bound with skin

If you answer this riddle you'll never get in

Searching for that finds nothing useful (just a lot of articles for The Incredible String Band).

I vaguely remember something about a maze, and (possibly) a comment that 'the fifth element is love'. Aside from this, I don't have much to go on. Still, I figured it was worth a shot.