I'm no scientist (obviously), but this strikes me as an argument against evolution:

The video shows what happens when one person draws a line, another person traces that line, then another person traces the tracing...etc. for 500 rounds.  The results diverge from "line" surprisingly quickly, and the latter iterations look more like a map of the UK than a set of the points whose coordinates satisfy a given linear equation.

I guess David's trying to say that the video demonstrates "things change over time" and since evolution means, in part, that "things change over time" this video demonstrates evolution; ipso facto, QED.  David had 140 characters in which to make his point, so I'm not going to penalize him for lack of nuance.  But one of the central tenets of Darwinian evolution is that changes advance species toward fitter versions of themselves, or new species altogether.  In either case, the advances are self-evidently functional improvements.  

This video merely shows how quickly and wildly an object can degenerate when its change relies on imperfect inputs.  And in the case of the people tracing these lines, its seems, mild retardation comes into play too.

Jason Kottke pointed me to this video.