The short film started with all these people in the middle of the square in some blue( ? ) void like space and eventually one moves, causing the whole thing to start to shift, so they all take a step forward. This happens until all of them end up at the edge of the square. They all look like the exact same person, down to their clothes.
Then they all pull out a fishing rod from their blue boats and start fishing. One of them ends up reeling in a heavy object, so the others run to the opposite end to balance out the square. The one guy ends up fishing up what turns out to be a big, square wind-up music box.
The remaining people all end up wanting it, so they all try to get it, but in the end there is only one of them who didn't get sent off the platform and he is on the opposite side of the platform to the music box, trapping him away from it forever basically.
I want to say it was from a German animator, but I can't remember if that's true or not. There's no dialogue whatsoever, so that doesn't help either. It's not from any time past the 2000s, that much I'm fairly certain of.
Any info is helpful and an advanced thanks is in order.
Like others have said, it's a continuation, but instead it's following a new Avatar in their journey. Probably the 2nd Avatar after Aang.
As far as I know, the plot is basically gonna be set in a seemingly post apocalyptic world where there are only something like 7 remaining havens/cities/whatever where humans can live because of his dangerous it is outside of them. I'm super excited to see how they handle it.