All signs, excluding awning and window signs, shall be constructed only from wood, metal, stone, or other material as determined by the Borough which has the general appearance of structures composed primarily of wood, metal, or stone with painted, engraved, or raised messages. Sign materials should complement the original construction materials and architectural style of the building facade on which they are to be displayed. If plywood is used, medium-density overlay shall be used as a minimum grade. Bare plywood is prohibited.