\Art\Terrain\tnt.pcx is the file that adds an overlay to grasslands, plains, desert, and tundra. some use it to create prettier terrain. others have posted a blips version that indicates shields and food
Cordy came up a tnt.pcx that had rocks and trees. BlueMonkey came up with one that had flowers. unfortunately to my taste the rocks and trees were too large, and the only flowers that show up well on my terrain are the red ones
the other problem is that only the second row of tnt.pcx gives any additional tile info, namely indication which of the grassland tiles have outcroppings and hence an extra shield. the other rows only serve serve to make prettier but potentially confusing terrain since no info is being added
I am posting a new tnt.pcx that addresses all these problems. I deleted all but the second row and then combined the rock, trees, and red flowers. the result is that grassland outcroppings (only) are clearly indicated and the terrain is still "pretty"
here it is
rocks, trees, and red flowers tnt.pcx 2016-10-05
rocks, trees, and red flowers tnt.pcx