A nice example of this issue.
Obverse: bust of the ruler to the right, in the outer rim the legend:
IOAN CASIM D G-REX POL & SVE;
Reverse: in the rim crowned shields of the Coat of Arms of the Crown of the Kingdom of Poland, the Grand Duchy of Lithuania and the Vasa dynasty, next to the Snopes initials T L-B, under the crown the denomination mark VI, in the outer rim legend:
GROS-ARGE-SEX-REG-POL-1660;
