Hello, I would appreciate some criticism, advice and help for this tileset I'm making. I wanted to start off with some hard ground/ rocks but they don't look as good as I want them to be.

I think the problem is within the rocks themselves, the shape and placement but I don't really know how to fix them. I don't want them to look too cartoonish though but I just don't know how to fix it. Maybe I will eventually need to redo them completely? Or should I use less colours than 4 for the vertical pattern?