The simplest design of the General Motors roller-press trial pieces. These were struck by General Motors Technical Center in Warren Michigan to test a new coin press. According to StacksBowers 8/22 sale, these date to June 1964. These were described as: "One of the earliest experimental cents produced by General Motors as part of the roller press project, these GM/MD pieces were struck on one of the first prototype presses using dies created by GM. The type is exceedingly rare with only two specimens currently known, both of which are being offered in this sale. This first-ever public offering for the type represents a fleeting opportunity for advanced collectors of pattern and related coinage produced by or in conjunction with the United States Mint." As noted in the description, two examples were offered in StacksBowers 8/22 sale. Photo courtesy of PCGS.