The illusion of a floating manhole cover is what I see, but my brain tells me that is not possible. Well seen and taken. I think you have come extremely close to an original Beguin.
Good tonal work on a subject with interesting textures and shade. A closer view of these three elements of composition could lead to some interesting results.
is this a found mandala, some medieval astronomy symbol, a lucky moment of the day or is it as Dante said (ah, a long lost latin from ages ago) corpus lunare est totem rotundum?