We have some evolution buffs here, so when I ran into This discussion linked by the Speculative Evolution tumblr, I had to share.
It's images are gone, but it's a writer coming up with some basic physics for a 2d universe and extrapolating the kind of life that'd evolve there over time, how they changed over eras, and their different adaptations.
2-D evolution
Moderator: NecronLord