Puzzle 15 and the disappearance of Marilyn Bergeron WKT7 #4

Have you heard of Puzzle 15?I bet you have, you just don't know it. You know those 4 x 4 tile scrambles where you have to rearrange the sliding pieces into an image? Popeye? The Flinstones? That's the 15 puzzle, sometimes called Gem, Boss, or Mystic ...