Are there restrictions on distribution of SP-D dimers in fuzzyballs

Looking through as many SP-D images as I could find in the literature I began to sense that the distribution (radial) of SP-D dimers was not random. I am determining the angle of separation of each arm of a SP-D fuzzyball to see if the numbers fall into classes of small, and larger. The data for these three pictures is spot-on.  Various authors are responsible for these electron micrographs, i give them credit..they are not my personal photos.

To create the round “generalizations” of angles in SP-D fuzzyballs, the actual angles were measured in the molecules below.  They a mean was obtained for each angle-set: e.g. the center pix had 4 measurements, as follows:  I will measure all 90 images and see if the trend holds.
147.46
127.6
41.62
43.32