David Sparks’s isarithmic history of the two-party vote, which adds gradations to choropleth maps of U.S. presidential election results, has been making the enthusiastic rounds of the Internets this week (Daring Fireball, MetaFilter, Talking Points Memo). The above video, which animates those maps to show nearly a century of presidential politics in just over a minute, is particularly dramatic. That said, David’s other work is also worth a look, including his attempt at k-means redistricting — redrawing electoral districts based on a minimum mean distance from each district’s centre — a link to which he sent me last month and I’ve been saving for you.