I have a 1991-D penny that has been struck multiple times but I would like to know the correct classification or term of this error. Also, the multiple strikes are mirror images, if you look on the reverse the "ONE CENT" is backwards, so I'm guessing this is caused by another penny/planchet being punched at the same time? If anybody can give me more information on this error and how it occurs, then I would really appreciate it. :smile Also, what would be the rarity of this error and are there links to other coins that have had this error? Thank you very much!