+-- Ground level --------------------------+
| |
| *--*--*--* |
| / \ |
| / \ |
| * * |
| / \ |
| / \ |
| *--* * |
| / \ |
| / \ |
| * % * |
| / |v / |
| / | / |
| * *--* * |
| \ / / |
| \ / / |
| * * * |
| \ / / |
| \ / / |
| * *--*>-*--* |
| \ |
| \ |
| * |
| \ |
| \ |
| * |
| \ |
| \ |
| * |
| | |
| | |
| * |
| v |
| |
+------------------------------------------+
+-- Level -1 ------------------------------+
| ^ |
| % |
| v |
| |
+------------------------------------------+
+-- Level -2 ------------------------------+
| |
| M |
| | |
| | |
| * * |
| | | |
| | | |
| * *--*--* |
| \ / |
| \ / |
| * * |
| \ / |
| \ / |
| *--* |
| / |
| / |
| * |
| | |
| |^ |
| % |
| |
+------------------------------------------+