SALT LAKE CITY — A message that has been showing up on city streets around the world recently popped up in Salt Lake City. It’s a mysterious image known as a Toynbee Tile, a small square containing a cryptic message for the public. The image has been painted onto roadways for decades, but to date, no one has been able to figure out who is behind it all. Recently, one appeared at the intersection of State Street and 200 South, conveying a message that read, “House of Hades. Tiles made from the ground bones of dead journalists.” The quote has...