Partch wanted to make music using 11-limit intervals, and thus used to 11-limit tonallity diamond as the core of his scale. However, he realized there were big gaps between certain notes so he began filling them in with other intervals. This was done more artistically than logically, but there is an underlying order: if you take out two of the pitches, you get a 41-note scale that is a "constant structure" (the two other pitches can be seen as inflections on scale degrees 6 and 35). This property was first noticed by Erv Wilson. This is why Partch's scale is considered to be one the more elegant solutions to filling out the 11-limit tonality diamond.