Generalizing to higher dimensions is straightforward. To construct the orbifold
Tn
/Sn, take an n-dimensional prism whose base is an (n–1)-simplex, twist the base so as to
cyclically permute its vertices, and identify it with the opposite face (Figs. S5, S6) (16).
The boundaries of the orbifold are singular, acting as mirrors and containing chords with
duplicate pitch classes. Chords that divide the octave evenly lie at the center of the
orbifold, and are surrounded by the familiar sonorities of Western tonality. Voice leadings
parallel to the height coordinate of the prism act as transpositions. A free computer
program written by the author allows readers to explore these spaces (19).