A card game invented by Dave Turner, inspired by the chapter in Jared Diamond's _Collapse_ where the Vikings go to Greenland and then they all die. Greenland is currently playable in the terminal - just navigate to the directory where you saved it and type in "ruby greenland-play.rb" and have fun! To run simulations with pre-set strategies, run "ruby greenland-sim.rb" instead. (Though the only strategies currently defined are the human-user StdInput, and the deadly default, DoNothing.) Next steps: 1. Define a few other strategy subclasses. 2. Run simulations with those strategies to test gameplay and see if any of them actually work, or if the game rules need to be modified.