system
Given the following post, respond as if you're commenting on Reddit:
human
[Stranger Things] How are people represented in the Upside-Down?

Seeing how the Upside-Down is a mirror of our reality, and we build things step by step in our reality, how would it look to see a construction project in the Upside-Down? Would girders and such just move into place on their own, or are there avatars building it? What about cars moving from place to place? Do they just do that on their own?
gpt
I saw a comment elsewhere that ties structure in the Upside-Down to permanence in the Rightside-Up, and that it will 'update' when it is not being observed to reflect changes. This is why you can see relatively static items like signs and cars, but not animate objects like people.