Pyramidal staircase maze

Sometimes, life is like this pyramidal staircase maze :)

[Maze generator](https://www.thingiverse.com/thing:1185425) is my first challenge of using OpenSCAD to generate a maze automatically. After that, [many mazes](https://www.thingiverse.com/JustinSDK/collections/maze-generator) were created. Some people were curious about how to implement these mazes. They were, actually, all based on Maze generator.

There are many different maze algorithms. If you are interested in them and want a beginning, a book I recommended is [Mazes for programmers](https://pragprog.com/book/jbmaze/mazes-for-programmers).

Honestly, maze algorithms are not very difficult. If you come from imperative languages, the hard part of using OpenSCAD to implement a maze may be the paradigm of functional programming.

The code of Maze generator is quick and dirty because it's my first challenge of using OpenSCAD to generate a maze. From that time, I've studied OpenSCAD for one year. One day I thought, ho