Unless you’ve recently rewatched the first season of “Stranger Things,” you might have missed some of the references to that freshman season in Season 4, which premiered on Netflix last Friday. Some callbacks were obvious — we all remember Joyce (Winona Ryder)’s joy at being able to communicate with Will (Noah Schnapp) through her Christmas lights, which is referenced in the Lite Brite scene — but here are a few you might not remember.