As of this point, here are all the puzzles you can unlock, thanks to Nintendo World Report.
http://www.youtube.com/watch?v=JwxRmEeKj74
Look pretty nice, although I doubt I'll ever even finish one given how few people own a 3DS round here.
http://www.youtube.com/watch?v=JwxRmEeKj74
Look pretty nice, although I doubt I'll ever even finish one given how few people own a 3DS round here.