and my answer is dwarf fortress.
dwarf fortress is a game that builds a deeply interesting simulation of little people who have lived and likes and dislikes and trauma and depression and they fall in love. they do a vast amount of things that real people do. they build complex social networks. they fight. they kill.
and they are not even alive, despite all that. they are some of the most complex virtual societies you can procedurally generate and they can't hold a candle to what we can do. to our social ties and feelings. i am in awe of the sheer scale of dwarf fortress as a piece of generative art and in awe of the infinite complexity of the real, unsimulatable world.
