Publisher's blurb: The Cavern-Tunnel Multiple Passages group of Naked Geomorphs contains 18 tiles, each with one cavern opening (CD, CSD) and three or more connected tunnels (T). Sets A and B are completely interchangeable. I.e., tile M106B can be replaced with tile M106A, without changing the basic structure of your map. Set B has broad, two-hex wide, tunnel passages branching off the larger cavern area.