type tuesday: 15 puzzle

As I read through the printer proofs of issue 15, I present these images of the sliding 15 puzzle to ponder. This puzzle, invented around 1874, involves 15 sliding blocks in random order, in rows of 4 with one tile missing. The object is to slide them back into numerical position.

According to Wikipedia: "The game became a craze in the U.S. in February 1880, Canada in March, Europe in April, but that craze had pretty much dissipated by July. Apparently the puzzle was not introduced to Japan until 1889."

i remember getting cheap versions as birthday party favours when I was a child.