Iron Mine Tunnel
================

+-- Ground level --------------------+
|                                    |
|                           *        |
|                          / \       |
|                         /   \      |
|               *--*--*--*     *     |
|              /                \    |
|             /                  \   |
|            *     *              *  |
|           /     / \             |  |
|          /     /   \            |  |
|  <S&-*--*--*--*     *           C  |
|         |            \             |
|         |             \            |
|         *--*           *           |
|             \          |           |
|              \         |           |
|               *--*     *     C     |
|                  |     |      \    |
|                  |     |       \   |
|                  *     *        *  |
|                  |     |       /   |
|                  |     |      /    |
|                  C     *--*--*     |
|                       /            |
|                      /             |
|               C     *           C  |
|               |     |          /   |
|               |     |         /    |
|               *     *     *--*     |
|              /      |     |        |
|             /       |     |        |
|            *        *     *        |
|            |       /     /         |
|            |      /     /          |
|            *--*--*     *           |
|                 /     /            |
|                /     /             |
|               *--*--*              |
|              /                     |
|             /                      |
|   %--*--*--*                       |
|   v                                |
|                                    |
+------------------------------------+

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

+-- Level -2 ------------------------+
|   ^                                |
|   %                                |
|   v                                |
|                                    |
+------------------------------------+

+-- Level -3 ------------------------+
|   ^                                |
|   %                                |
|   v                                |
|                                    |
+------------------------------------+

+-- Level -4 ------------------------+
|   ^                                |
|   %                                |
|   v                                |
|                                    |
+------------------------------------+

+-- Level -5 ------------------------+
|   ^                                |
|   %                                |
|   v                                |
|                                    |
+------------------------------------+

+-- Level -6 ------------------------+
|   ^                                |
|   %                                |
|   v                                |
|                                    |
+------------------------------------+

+-- Level -7 ------------------------+
|   ^                                |
|   %                                |
|   v                                |
|                                    |
+------------------------------------+

+-- Level -8 ------------------------+
|   ^                                |
|   %                                |
|   v                                |
|                                    |
+------------------------------------+