Figure 6a. (See 6b below.) Histogram of frequency measurements for Song No. 1. (Constructed from data produced by Sigmund.) The prominent peak corresponds to the baseline pitch; the remaining measurements are spread fairly evenly across the higher frequencies, but with some possible local peaks apparent. This can be taken as evidence in support of baseline/tumbling-strain --> stasis/motion idea.

Figure 6b. Histogram of upper frequency components for Song No. 1. (Constructed from data produced by Sigmund.) Some local peaks are apparent, suggesting the existence of localized stable pitch areas within the tumbling strains.