Check out the peg underneath one of the granulated discs

Untitled8aThis is a closeup of one of the concave granulated discs. At this level of magnification, you can easily see the peg it is resting on. This peg goes through the backsheet and is covered up by a small dome on the back. Also notice how easily you can see the seam in the wire circling the dome. Some slight damage to the back pushed this particular peg up a bit, making it a little higher and easier to see than the others. Although pristine ancient pieces are beautiful to look at, damage often reveals construction details that are difficult or impossible to see otherwise. Hurray for damage!