Abstract: A window case includes a main frame formed of a pair of vertical sections and a pair of horizontal sections. Each section has an outwardly open U-shaped channel extending longitudinally along the section, each channel having a front sidewall, an inner bottom wall and a rear sidewall opposite the front sidewall. A limb extends longitudinally along each of the sections and frontwards from an outer edge portion of the front sidewall thereof. The limbs of each of the vertical sections and the horizontal sections together define an intermediate window frame. A pane frame securing a window pane is mounted on the intermediate window frame.

Abstract: A panel structure for a building panel system to cover an exterior wall of a building. The panel structure comprises identical frame members fixed to the back surface of the panel, one along at least two of its edges. The frame members have mounting portions projecting away from the panel, each two opposed hook. The mounting portions of frame members extending along opposed edges of the panel are in longitudinal mirror symmetry to each other, so the panel structure does not have a specific orientation.