[PD] phasor~ usage question

[PSPunch]

Hi,


Can someone please give me a bit of info regarding the example
illustrated in the page,
http://crca.ucsd.edu/~msp/techniques/latest/book-html/node198.html


> Each parabolic wave is computed from a sawtooth wave (ranging from
> -0.5 to 0.5) by squaring it, multiplying by 0.5, and subtracting
> the DC component of -1/12, or -0.08333.

I could not quite understand where this offset of 0.08333 comes from.
Are there any descriptions of the theory behind this?


Also, this example has a message connected directly to [phasor~] while a
good number of other samples (including the [phasor~] help file) has a
[sig~] in between.
Is there any difference in the behavior?

Thanks.

--
David Shimamoto