50 State Quarters to form what is known as a "mule". Only sixteen of these specimens, produced on dollar planchets, escaped from the mint. A 2005 Minnesota double die quarter, as well as a 2005 Minnesota quarter with extra trees (another die error), have both triggered numismatic interest. An unusual die break on some 2005 Kansas quarters created a humpback bison. Relatively more common are Kansas quarters bearing the motto "IN GOD WE RUST." The United States produces proof coinage in circulating base metal and, since 1992, in separately sold sets with the dimes, quarters, and half-dollars in silver. For the silver issues,
Major thirds tuning often added to restore the standard E-E range. While M3 tuning can use standard sets of guitar strings, specialized string gauges have been recommended. Besides this M3 tuning, which has the open notes {G, C, E}, there are exactly three other M3 tunings, which have distinct sets of open-note pitch classes. The other major-thirds tunings respectively have the open notes {A, C, F}, {A, D, F}, and {B, D, G}. For six-string guitars, the M3 tuning loses the two lowest semitones on the low-E string and the two highest semitones from the high-E string in standard tuning; it can use