> Please use your imagination and try to imagine one of infinitely many other streams that I could make at runtime that are not easily made with the built-in toy oscillators.
Somebody already did. Check out Fourier Theory. The oscillators (well actually just sin, the rest will give you some help as well) can be used to make any stream, technically.
Ah yes, just run a square wave at twice the range of human hearing, then use a combination of filters to extract the desired ranges. Unfortunately you'd also need an infinite arrangement of filters.
