Orchestral-Instrument Aperiodicty Yet Again

I looked over a variety of sounds in the sound library I used for
testing the sound analysis program I worked on for a few years several
years ago. I'm now willing to accept that this effect of little peaks and
troughs in a sound bobbing up and down in a tone is not nearly as common as
I recalled it to have been. In fact when I picked out that example tone to
post as that GIF file, I'm amazed that I chanced upon a sound file that
shows that effect on just my second try.

Just now I looked at 20 or so fundamental-mode waves, and only noticed 2
that showed apparently systematic aperiodicities. There were plenty of
random fluctuations though, not surprisingly.

So until I now in this discussion, I was willing to accept Paul E's
theoretical model predicting exact periodicity was probably a good model,
but not a completely infallible one. I assumed from having seen systematic
aperiodicities that it was valid for the basic variables, but that there
apparently was some smaller consideration that it didn't take into account.

But looking over quite a few applicable waveforms just now, has
increased up my confidence in Paul's model by a factor of 10 or so.
Systematic aperiodicities of the sort that seem to suggest not-quite
completely harmonic partials in typical orchestral instrument sounds do
indeed seem to be quite rare.