The “cross formy” was drawn with concave sides, as in the illustration, from c.1280 (in the arms of Ekont [ANA2 315]) throughout the Society’s period. Beginning in the 16th Century, it was also sometimes drawn with straight sides. The arms may converge to a single point at the artist’s discretion; the splay of the arms should be pronounced.
Dorothea of Caer-Myrddin bears: Argent, a cross formy sable.
Edmund Cavendish bears: Per bend azure and gules, a cross formy Or.
Domnall na nAmus bears: Vert, three crosses formy Or.