2013-03-25 Archiv

Musical Doughnut.

The topology of the syntonic temperament's tonnetz is generally cylindrical. Any syntonic "equal" tuning (i.e., a tempered width of the perfect fifth which divides the octave into a number of equally-wide intervals) snaps this cylinder into a torus(the shape of a ring doughnut, a hula hoop or an inflated tire), showing that it has a topology equivalent to S1×S1.

Wikipedia: Tonnetz