I was having a difficult time trying to visualize what the path to residency looks like for each specialty. All of the information is freely available online, but I was unable to find a concise diagram that had all of the information in one place. I used LucidChart to make the below image. This list is not exhaustive but gives a very good overview of how each residency fits in with one another.
I planned on expanding the diagram to include how each residency fits with fellowships but already Jon Coleman did I much better job than I could have.