Mint-made errors 5 centavos. Foreign coins struck on a U.S coin planchet or vice versa are very uncommon and hold a high value. Authentic error coins should not be confused with coins that are damaged after being minted, which is known as post-mint damage (PMD) or post-strike damage (PSD). Mints purchase long strips of metal which are fed through blanking machines that punch out disks known as blank planchets (or simply as planchets or blanks) on which coins are struck. This determines the size and shape of eventual coins. The punched disks are first known as "type-1 blanks (or planchets)". The disks
Eight Pieces for Four Timpani Eight Pieces for Four Timpani Eight Pieces for Four Timpani is a collection of short pieces by Elliott Carter for solo timpani – four drums played by one musician. Six of the pieces were composed in 1950. Two new pieces were added in 1966, and the rest were revised in collaboration with percussionist Jan Williams. Carter wrote the pieces as studies in tempo modulation and the use of four-note chords. They are a collection rather than a suite, as Carter suggested no more than four be performed at once. The pieces make heavy use of extended techniques, including playing with