Publisher's blurb: The Tunnel Passage and Deadend group of Naked Geomorphs contains 30 tiles, each with a pair of connected tunnel entrances (T), another deadend tunnel entrance (T) , and rock (R) at the three remaining positions. Sets A and B are completely interchangeable. I.e., tile T89A can be replaced with tile T89B, without changing the basic structure of your map. Set A has narrower tunnels than set B, with lots of one-hex-wide passages, small to medium galleries, and a fair amount of deadend branching.