In Dexter's newest episode, they re-enacted the American Gothic painting by Grant Wood and it's pretty hard to miss -there's a scene where Rudy/Brian stands next to Dexter while Dexter is holding a pitchfork in front of the painting of the house from American Gothic.
Wikipedia reads about the original painting:
" the man's pitchfork symbolizing hard labor, and the flowers over the woman's right shoulder suggesting domesticity."
In the frame above, we see a tractor's engine over Dexter's shoulder.
There's also the sign in the painting that reads 124.50, which bring to mind the messages from Doomsday Killer, which went on like 1237, 1242... maybe I'm just reading into it but it would be great if they embedded plot clues into the environment's design.
For the sake of not giving any spoilers, I shall not go further ;)