Developer Matthew Applegate has released Sonus (Six) - a "digital referee for 12-note serial composition."
Users tap on a block, releasing the pitch contained within it. Once released, the block extinguishes itself.
This continues until as per the rules of 12-note composition, all twelve boxes have been utilised and they are free to return to play.
The software in part inspired by the work of Arnold Schoenberg, with Sonus (Six) adding the dimesion the uknown note contained in the box. According to the developer, this not only allows for each note to be of equal importance, but allows the performer no preference of known order.
Sonus (Six) is part of a collection of digital instruments designed and programmed as the culmination of three years of Masters Degree research in to alternative musical instrument.