In this picture they are chicken wire with newsprint attached to it. Then black and gray spray paint. Just sprayed the 'cracks' and then blended out a little with the gray. This year, to help with durability, we made rock walls with black landscape fabric and spray painted with light gray and med gray to hightlight the high spots rather then shadow the low spots since the landscape fabric we used was black. We use this stuff to make tree trunks too! Its awesome and doesnt tear apart.