The display is Audacity (free).
Mine never had a chance to bloom.
Yes. It shows in the spectrum, but at -31dB for 200Hz, where the square spectrum registers 0dB for 200Hz:
Tweeter:
View attachment 73199
I didn't explain my view correctly, either.
Start with a sine of f1, it has no flat, and no edges.
The higher odd harmonics add to create the "attack", and partially add to fill above the slope of the F1 sine, and cancel at the peak of the F1 sine, is how I think of it now.
The math proof? I dunno. Here is a sine and the first two odd harmonics at 1/3 and 1/5 amplitude building toward a square wave.
View attachment 73203
At the first zero crossing all three components are going positive (adding) so their sum is more positive than the F1 sine at those points, at the peak of F1 they alternate phase (cancellation), and the sum (mix) reveals that.
The higher harmonics continue with a similar pattern, filling the gap between sine (F1) and square in a similar manner.
The second graph is the decibel representation of the sample points in the tweeter wave.