[sdiy] Wavetable info

[Grant Richter]

> Um, well, actually that's the hard part.  You have to do a lot of
> experimenting.
> I have managed to divine a couple of rules:
> 
> 0.  Start with simple stuff, like sine waves, and work your way up.
> Even things that you think are standard, like pulse waves, may
> surprise you when you draw them.

If you consider impulse exciting a filter, you will produce a decaying
sinusoidal where the number of "waves" corresponds to filter frequency, and
the decay slope corresponds to filter resonance.

If you had a set of draw tools which could achieve the effect, and then
added different copies, you could draw a formant excited by an impulse
function (such as the edge of a square wave or sawtooth reset).

This could provide better access to music tones than a typical set of draw
tools like lines and dots.