I really struggled with this one. I was blown away by Maya [link]
and started out to make something similar. A pleasing pattern, some light relief, and maybe a bit of grunge. But nothing even came close. So I spent a lot of time just trying to nail down the right pattern and discarded them all. I tried several from Squidfingers but nothing worked for me. So I went back to basics and did this simple dot pattern thing. Then I added a little relief. And all of a sudden I had something I really liked. Then came the lighting. That took a lot longer than I thought. But here it is. Enjoy. This is probably the first thing I've posted here that I actually like.