Grand Tour Puzzles involve a grid of points that all need to be connected by a single loop. To begin the puzzle, a few of the points are already connected to insure a unique solution. There is a great resource for Grand Tour puzzles on the web here. Also, for anyone interested in the math behind the puzzle, check out this page. Enjoy!
With consent of Glenn Iba you can find an online version of his puzzles here:
http://www.janko.at/Raetsel/Grand-Tour/
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