Ruby で迷路作成（コンソール版）

ここでグラフィカルな迷路を生成してみたのですが、やっぱりコンソール版も欲しいよねということで作りました。
　
こんな感じ。

*****************************************
*           *   *   *   *   * *         *
*** * * * ***** * ***** * *** ******* ***
*   * * * *       * * *       *   *     *
******* * * ******* * *** *** * *** *** *
*   *   *               * * * *   * *   *
*** ******* * * ***** ***** * * ***** ***
*     *   * * * *         * *     *   * *
* ******* *** *** ******* * *** * *** * *
*             *     *         * * *     *
* ***** * *** ******* * * *** * ***** ***
*   * * * * *     * * * *   *           *
*** * * * * * ***** * *** * ***** *** ***
*     * * *   *       *   *     * *     *
*****************************************

どうですかね。

コード。
maze_another.rb

class Maze
  def initialize(x, y)
    raise "maze size error" unless x.odd? and y.odd? and x >= 5 and y >= 5
    @x, @y = x, y
    
    @field = Array.new(y) {Array.new(x, 0)}
    co = 1
    1.step(y - 2, 2) do |j|
      1.step(x - 2, 2) {|i| @field[j][i] = co; co += 1}
    end
    
    @a, @b = (x - 3) / 2, (y - 3) / 2
    @lx, @ly = @a * (@b + 1), (@a + 1) * @b
    @remain_wall = (0...(@lx + @ly)).to_a
  end
  
  def generate
    break_wall until finish
    @field
  end
  
  def break_wall
    wall = @remain_wall[rand(@remain_wall.size)]
    @remain_wall.delete(wall)
    if wall < @lx
      x, y = wall % @a * 2 + 2, wall / @a * 2 + 1
      return if (m = @field[y][x - 1]) == (n = @field[y][x + 1])
    else
      wall -= @lx
      x, y = wall % (@a + 1) * 2 + 1, wall / (@a + 1) * 2 + 2
      return if (m = @field[y - 1][x]) == (n = @field[y + 1][x])
    end
    @field[y][x] = m
    m, n = n, m if m > n
    replace(m, n)
  end
  
  def replace(m, n)
    1.upto(@y - 2) do |y|
      1.upto(@x - 2) {|x| @field[y][x] = m if @field[y][x] == n}
    end
  end
  
  def finish
    a = @field[1][1]
    1.step(@y - 2, 2) do |j|
      1.step(@x - 2, 2) {|i| return false if @field[j][i] != a}
    end
    true
  end
end

def show_maze(field)
  field.each do |line|
    puts line.map {|x| x.zero? ? "*" : " "}.join
  end
end


field = Maze.new(41, 15).generate
show_maze(field)