Knight's Tour Puzzle comes from Carlos Magan.  The object is to place your knight on the board and move to all the squares exactly once.  Carlos has done a great job of introducing interesting shapes.
A true story: 30 years ago I was sitting in a pointless grad school class. The fellow next to me introduced this puzzle to me. The 5x5 grid.  Loved it.  The class seats were arranged in an open rectangle.  I always waited for the professor to sit first. Then I would sit on the same side, as far away as possible.  The class was stupid and pointless! But required. (Like a lot of education courses unfortunately)  I attended every class for 14 weeks. And did these Knight's Tour puzzles.  I solved all the grids from 5x5 to 15x15.  And proved that all nxn where n>4 is possible.
I wrote 2 papers and got a B+.

There's more to the story of how bad that professor was. You'll have to ask me in person for the rest. But don't we all have stories of boring/meaningless classes"
https://itunes.apple.com/us/app/knights-tour-puzzle/id1454835958"mt=8

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