Place A to Z within the 26 squares below, so that all alphabetically neighboring letters are in neighboring squares, or connected by a green path. It turns out that A and Z can be in any two squares, and the puzzle is still solvable. For one of the harder puzzles, put A in square 2, Z in square 6, and then find a placement for B to Y that works.
Puzzles provided by Wolfram Research, Makers of Mathematica