Fifteen puzzle solvability, Numworks Python

[rprosperi]

(04-26-2020 05:23 PM)Don Shepherd Wrote:  Back when I was a teacher, I would do what Sam Loyd did many years ago, present a puzzle with only two numbers switched and see if any of my students could solve it. Of course, after a few minutes of failures they would cheat by physically removing a piece from the board and inserting it where it belonged!

In addition to being a puzzle, seems this was a bit of an integrity checker as well...