Polyphony and monophony in instruments harpejji and the Chapman stick). Multiphonics can be used with many regular wind instruments to produce two or more notes at once, although this is considered an extended technique. Explicitly polyphonic wind instruments are relatively rare, but do exist. The standard harmonica can easily produce several notes at once. Multichambered ocarinas are manufactured in a number of varieties, including double, triple, and quadruple ocarinas, which use multiple chambers to extend the ocarina's otherwise limited range, but also enable the musician to play more than one note simultaneously. Harmonic ocarinas are specifically designed for polyphony, and in these instruments the range
Quadruple-precision floating-point format the double-double technique above, although that technique does not implement IEEE quadruple precision), since direct hardware support for quadruple precision is, as of 2016, less common (see "Hardware support" below). One can use general arbitrary-precision arithmetic libraries to obtain quadruple (or higher) precision, but specialized quadruple-precision implementations may achieve higher performance. A separate question is the extent to which quadruple-precision types are directly incorporated into computer programming languages. Quadruple precision is specified in Fortran by the codice_2 (module codice_3 from Fortran 2008 must be used, the constant codice_4 is equal to 16 on most processors), or as codice_5, or in