keys based on designs by Siemen Terpstra. This is now become the Lumatone Isomorphic Keyboard. Hex is a free software MIDI sequencer, which uses a generalized keyboard in place of the standard piano keyboard. Lanes are extended from the keys and MIDI notes can be drawn into each lane, and edited, with the mouse (as in a standard MIDI sequencer like Logic, Reaper, SONAR, etc.). The layout can be sheared to ensure that the vertical height of each key (and note lane) is proportional to its pitch height—regardless of the tuning used. A wide variety of isomorphic layouts are possible, including Bosanquet and Wicki. See also Isomorphic keyboard Linear temperament Pitch space Chromatic button accordion References Notations R. H. M. Bosanquet (1876) An Elementary Treatise on Musical Intervals and Temperament Macmillan & Co. London R. H. M. Bosanquet (1879) "On the Hindoo division of the octave, with additions to the theory of higher orders" Proceedings of the Royal Society of London vol. 26. pp. 272–284. Arthur Fickénscher, "Polytone Keyboard" United States Patent 2,232,600. February 18, 1941 Adriaan (Daniël) Fokker (1955) "Equal Temperament and the Thirty-one-toned Organ" Stichting Huygens-Fokker B. J. A. Pels "L'orgue accordé en cinquièmes de ton du Musée Teyler a Haarlem" Stichting Huygens-Fokker Erv Wilson (1974) "The Bosanquetian 7-rank Keyboard after Poole and Brown" Xenharmonikon v. which preceded more important papers on keyboards found in "Wilson Archives-Keyboard designs/Related to the scale tree Hanson, Larry (1989) "Development of a 53-tone Keyboard Layout" Xenharmonikon v. 12 John S. Allen (1997) "The general keyboard in the age of MIDI" Joseph A. Paradiso (1999) "Keyboard and Tactile Interfaces: American Innovations in Electronic Musical Instruments" NewMusicBox Wolfgang Fuhrmann (2001) Bevor die Musik sich ins Uferlose verliert Berliner Zeitung Online Footnotes External links Antonia Weisse, "Orthotonophonium" (Bildarchiv Preussischer Kulturbesitz) Keyboard of Bosanquet's Enharmonic Harmonium" (Science and Society Picture Library) Dave Keenan KeyboardMapper.xls (Keyboard mapping spreadsheet) Gene Ward Smith Bosanquet Lattices Stichting Huygens-Fokker Archiphone Harold Fortuin The Clavette Alain Danielou Center Semantic Daniélou Cortex Design Lumatone Isomorphic Keyboard Peter Davies Opal Chameleon Isomorphic keyboard layouts Microtonality