The Arc of Truth

Watching Stargate with the commentary tracks on has led me to consider the nature of plotting narrative over a long serial text. The idea of an "arc" is of particular interest--why such mathematical a term? Should stories really be "plottable"? What would a graph of a series actually look like? What about the financial, production-controlled aspects of a serial narrative?
Given the right information, could a television writer use the desires and narrative conventions of fandom to better control an audience? Do we really want fans writing our canon stories (yes, I'm still angry at Russell T Davies. But Martin Gero, this is for you, too).

Pendulum

This isn't the story he wants to tell
he makes her fall, cloying sweetness gone,
he makes her fly, volition lost in plumbing depths
that plumb three years later, carrying her closer to Xeno's mark

He shapes the world with steep arcs
smooth sines dipping below to break the zero line
he threw her down to this cupped pit to ride the curve
to cushion the rough universe plotted hastily against blue grid squares.

Drabble

Or, Amy Tries to Cope with Torchwood: Children of Earth

He doesn’t try to fix it, for once. He stands there and lets time wash over him and space move around him. And still he is not still, but hurtling around the sun as the rest of us flip our daily coins: to be or not to be? And the odds are always the same, anyway, half and half, maybe a little less, if you’ve got a nickel with the thick raised head of what’s-his-name. He lets the coins drop without tossing his own or tripping over all the spare change rolling around. All the day you’ll have good luck.

RUSSELL!