Not op art, but nature creating art. Small red ants apparently found a few soft spots between the herringbone courses of bricks. Their digging resulted in perfect circles of soil and ant castings, creating a pattern reminding me of Mondrian (again) (where do we get these inspirations anyway?).
It was right there on the sidewalk between two buildings, accounting for the indirect light on the bricks that appears to be a watery glaze; these paving bricks actually are glazed, but it isn’t always obvious without the right lighting. Not retouched at all, those are the native colors, subtle, muted.