Publisher's blurb: The Tunnel Wye and Passage group of Naked Geomorphs contains 15 tiles, each with a trio and a pair of connected tunnel entrances (T), and rock (R) at the remaining position. Sets A and B are completely interchangeable. I.e., tile T150A can be replaced with tile T150B, without changing the basic structure of your map. Set A has narrower tunnels than set B, with lots of one-hex-wide passages and a few small to medium galleries.