Our fish is a high relief subject that breaks out into the frame.
Lowering the frame causes effectively pushes the fish forward, to appear much bigger and sets off th fish. Thus, the frame is a very important part of this carving - or rather or this design: if you were to remove it entirely you'd still have an interesting, good-looking fish, but not a pierced relief of course, just profiled.
You'll see that I treat the frame as a bit of high relief carving; it just happens to be/look like a 'frame'.