It was stacked, probably, in ancient days but nobody knows. Then, the question is how to stack them again now because the challenge says “Get really creative. Stack things that are similar or very different from each other. Create your own pyramid or some other geometric shape.” So I have just edited my photo, rotating slightly, removing chroma, giving square shape and vignetting. I hope it works well.
A contribution to A Photo a Week Challenge: Stacked by Nancy Merrill Photography.