A quarter of the central starting square forms an axially symmetrical structure extending to four by four elements. The length of a double grid field of the side now represents the relative size for the ratio of the Golden Section in the inner grid field. Added to this is the intersection point of two arcs of a circle both from the diagonal and from the side of a grid field. The found line develops, relating to the axial centre, into the centred square. This square represents the actual centre of the building.