28:7 · The diagonally placed square in a square, , signifies a tank trap in some military systems.
    In heraldry, can appear high on a woman's coat of arms showing that she is divorced. ( and have the same meaning in a genealogical context.) Note that was the shape of a woman's coat of arms when noble ladies were allowed to have their own coats of arms at the end of the Middle Ages, around the year 1500.