Fibre is found in strange places

While I was looking for the photo I posted yesterday I came across a folder with a collection of pictures I took a couple of years ago at the last remaining ammunition dump at Woodmams Point. During World War II they were partially underground bunkers surrounded with high walls of cement filled sandbags, two metres or more tall, used for storing ammunition.
There used to be several of these buildings, but they are now all gone but one. The building is in very poor condition and covered in grafitti, but somehow the walls have survived without defacement.

And the fibre connection? The original sandbags have long ago rotted away, but have left their textural marks on the cement. You can clearly see the weave of the cloth, the seams of the bags and the stitching that closed them. And even, though not in this photo, frayed holes where sand spilled out.