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,
What Love Is Made Of dance music. She then got a bassline which made her "want to dance", and included it in the track. She also told the website that she wrote the song about the "feeling of love, what one person can give to you that someone else can't". What Love Is Made Of" was premiered during Irish DJ Annie Mac's eponymous program on BBC Radio 1, on 10 May 2013, though its digital download only occurred on 5 July 2013. It was serviced as an extended play, where it was bundled with three remixes, by MK (Mark Kinchen), Felix da Housecat and Brackles.