Interesting;.....Am wondering though if what we see is a relection off the glass. I drew an arrow to what looks like a concave image, refecting what may be the inner convex side of the window coaming, off the glass, ( note gap between).The images seem to compliment each other in form. The green lines I drew at the tops/ bottoms of shapes, almost appear like mirror images of each other,....angles going opposite each other as a mirror reflection may do. Just my opinion at the moment....but subject to change.