Arthur keeps a picture of his dog Copper, who passed away, next to his bed. I think it's a reference to the Disney movie The Fox and the Hound. The hound dog in the movie is named Copper. In the movie the dog Copper is best friends with a fox, Tod, when they're young. They become enemies as adults, then they each save each other's life at the end of the movie. It reminds me of Arthur's disillusionment, Dutch's betrayal, Arthur's sacrifice to save John, then Dutch killing Micah to avenge Arthur.

One quote from the movie always gets me- "Forever is a long, long time, and time has a way of changing things." I could definitely hear Arthur saying that.