###.t holds the tilemap for a map. It it comprised of two sections: A header, and a body. The header is in the Standard Header format, where as the body is simply a flat array of tiles, size width * height (with each type consisting of 2 bytes). Each layer has such an array, so the final lump size will be 2 * width * height * layers + header.
|INT||0||Standard Header Magic Number (0x1234)|
|INT||2||Header Size (0x8, but may vary in future versions.)|
Each tile's position can be defined using this formula: 2 * (layer * width * height + y * width + x), where x and y are the tile's co-ordinates, width and height are the size of the map, and layer is which layer the tile is on (0-2). Thus, the offsets listed below are relative to this formula.