I was going about in my typical atypical way and by chance did discover a very attractive fractal that is the frequency spectrogram of a swept triangular wave. I made this quick and dirty animation of a ping-pong zoom of it:
This was done with Audacity, GIMP, and NCH Tone Generator, all of which are free--my thanks to everybody who ever contributed code to any, it should be known that my thanks is an exponential function, for anybody who may have contributed to more than one. Also, thanks to anybody who understands any of what I write.
It should be noted that a number of other interesting fractals can be generated, depending on the wave type and the sweep.