The image to the left is an example of Lincoln Cent
A brockage occurs in the following way: A coin is
struck, then not properly ejected. A new planchet
is fed and the former coin overlaps the new
planchet. When the die strikes the coins, a mirror
image of the first coin is sunk into the next coin.
The initial coin may or may not become a capped
Most brockages, like the one to the left, are partial.
Full brockages, where the coins are completely
overlapping, are the most desirable.