The designs of cast iron fire backs used to be carved into wood and then it was transferred to moist sand to make the mold. This, obviously, created a negative image of the art and molten iron was then poured into the mold. Back in the day, the most widely desired designs included floral motifs, coats of arms and allegoric scenes. Decorative fire backs were very common with top featuring an arch or some other form of ornamentation. Stove plates were sometimes recycled and used in place of fire backs. Usually, if you find an antique fire back that is square or rectangular, it was once used as a stove plate. The art displayed on stove plates were most commonly biblical images and Psalm verses. German, Pennsylvanian households did this quite a bit.