About 130 of these mysterious hand-made tiles with messages have been found in many US cities. Who made them?

There are about 130 mysterious tiles embedded in tar roads in many US cities and even in Brazil, Argentina, and Chile. They carry bizarre messages and even more bizarre subscripts. Nobody knows who is responsible for the tiles and how he manages to leave them on roads without being noticed, as some of the roads are busy 24/7.

They are generally about the size of a license plate, and each had some variation of the same strange message: "TOYNBEE IDEA IN KUBRICK's 2001 RESURRECT DEAD ON PLANET JUPITER." Many of them had strange footnotes like "Murder every journalist, I beg you," and "Submit. Obey." Some even had lengthy, paranoid diatribes about the news media, Jews, and the mafia.

The tiles all mention "Toynbee"—most likely Arnold J. Toynbee, a religious historian born in England in 1889. Some of the tiles mention Kubrick, the filmmaker responsible for 2001: A Space Odyssey, a movie that implicated that a man was reborn on a mission to Jupiter.

The mystery of the tiles gave birth to a culture of tile enthusiasts who tirelessly try to solve the mystery of the 'Tile Man's' identity and the message behind the messages. Despite finding a few links and some background information, the purpose and message of these tiles remains inexplicable.

(Source)