<_description>
Generates random mazes, with three different algorithms: Kruskal,
Prim, and a depth-first recursive backtracker. It also solves them.
Backtracking and look-ahead paths are displayed in different colors.
https://en.wikipedia.org/wiki/Maze_generation_algorithm
https://en.wikipedia.org/wiki/Maze_solving_algorithm
Written by Martin Weiss, Dave Lemke, Jim Randell, Jamie Zawinski,
Johannes Keukelaar, and Zack Weinberg; 1985.