environment tiles

[Vipershark]

The only issue I really see is that your changes in color all use the same pattern so they kind of stick out from each other.
Look at the "U" section near the middle with the light part surrounding the dark just under the grey strip there. Because the grass follows the same pattern even though the color changes, I feel like that sort of causes your eye to be able to see the pattern better since it continues to loop across the color change.

It's... kind of hard to express in words but it's sort of like... when I look at it, it just makes me... "predict" the pattern...? I dunno. My eye sort of "pulls out" the pattern by seeing it continue along the line of different colors.
Basically I guess what I'm trying to say is change up your pattern with each color, but try to get them to still blend together at the edges of each color change if possible. That will likely drastically increase your individual tile count but it would help a lot as far as realism goes, I think.