Figure 3: Pitch occurrence frequencies within specific pitch sets articulated in Herma. Bullets indicate notes which did not occur in the given section. Shaded areas represent "best-guess" versions of the sets A, B and C and sets algebraically computed from them. As in hexadecimal notation, the decimal numbers 10, 11, 12 . . . are represented by the capital letters A, B, C . . . so that all entries in the table are single characters.
Robert A. Wannamaker, Structure and Perception in Herma by Iannis Xenakis, Music Theory Online 7.3 (May 2001)