In each case, this needed to be consolidated by hammering it into a more regular shape. This was done manually with heavy hammers; later by a waterwheel or steam powered hammers, leading to modern power hammers. The result was an oblong-shaped iron product similar in appearance to shingles used on roofs.
In each instance, this required to be shaped into a more regular form. This was accomplished manually using heavy hammers; later by waterwheels or steam-powered hammers, leading to modern power hammers. The outcome was an oblong-shaped iron product resembling shingles used on roofs.