I think it will be something long without arms or legs, like a dragon.
The letter X represents the buck and antlers. The letter Y is how the bird legendary's wings are shaped, 2 on the side and one on the tail just like the letter why.
So for Z, it'll probably have to be shaped like the letter Z, hence no arms or legs, just a straight or zig zag line. --- I hate seeing sigs with PC specs on them. PSN: tookhster ------ Proud owner of a Wii, PS3, 360, 3DS, Vita, and now a Wii U!