Forget the math aspect of it. The fractal is an image with a huge amount of depth (because it never simplifies). If you want to get technical, the fractal never simplifies, and so it's infinitely detailed, but obviously Beethoven's music isn't. And while i agree that the word "meaning" is subjective, "depth" isn't (at least in the way i meant it

). Depth being how far you can analyze a piece of music.
Anyways, the metaphor was focusing on the images in relation to music. One looked great, the other had many layers to be appreciated.
[offtopic below!]
also @ benjamin
Quote: "Show me something mathematically generated that has the depth and complexity of something in nature, and I'll be impressed."
Well...
math in relation to nature:
there are equations that accurately simulate the flow of water, mathematics that can tell if a building will collapse, where a hurricane might go, how fast a cloud system moves, show the behavior of a beam of light, depict the smallest particles, get satellites into space looping around planets, etc.
math being able to look like nature:
Rendering, 3d graphics, all those CGI effects.
math with the complexity of nature:
most fractals (the 3d fractals are especially stunning), particle physics, regular physics, etc.
But anyways, expanding on herakles's point, math is just another way of analyzing nature. I would also say that the human brain is just another way of analyzing nature.