Spiral Stairway
===============

+-- Level +1 ---+
|               |
|      %        |
|      #v       |
|     ^|^       |
|      M        |
|               |
+---------------+

+-- Ground level ---+
|      ^            |
|      %            |
|      |            |
|      |            |
|   *--*#-*         |
|    \              |
|     \             |
|      %            |
|      v            |
|                   |
+-------------------+

+-- Level -1 ---+
|               |
|      *        |
|      v        |
|               |
|               |
|               |
|      ^        |
|   *  %        |
|   #  v        |
|   |  ^        |
|   *--*--%     |
|        /v     |
|      ^/       |
|      %        |
|               |
+---------------+

+-- Level -2 ---+
|               |
|      %        |
|     v|\       |
|      | \^     |
|   *#-*  %     |
|      |        |
|      |        |
|   *#-*        |
|               |
+---------------+

+-- Level -3 ---+
|      ^        |
|      %        |
|     /         |
|    /          |
|   %--*--*     |
|   v  #  #     |
|      |  |     |
|      *  *     |
|               |
+---------------+

+-- Level -4 ---+
|   ^           |
|   %           |
|    >          |
|               |
+---------------+