Sixxen  

The sixxen is a metal-keyed instrument invented by Xenakis for his composition Pleiades. It is tuned mathematically to produce six sets of micro-tonal scales, each consisting of 19 notes (see picture). This design produces a clash of harmonic overtones and shimmering glissandos. It's name is a combination of the words 'six' and 'Xenakis'.