if you set a world border to a big size (like 30 blocks) and set the center past x/z 29999983 and then shrink it to a small size (like 1 block) and add a time that it will shrink then the world border will look rectangular, then weird like a 2 sided world border, but later it will ** crash your game.
Do NOT try this on your worlds or on your servers! It may PERMANENTLY crash your world/server!
Steps to reproduce:
- Create a new world with creative game mode;
- Type in chat "/tp 29999950 100 0" (this should teleport you at the edge of the world);
- Type in chat "/worldborder set 30" (this should set the world border to a small, but not that small size);
- Type in chat "/worldborder center 29999990 0" (this should center the world border past 29999983 x/z);
- Type in chat "/worldborder set 1 20" (this should shrink the world border to 1 block in 20 seconds and crash the game);
- Watch the world border shrink, become messed up and rectangular, and then messing up your game too and crashing it;
Because the attachment video exceeds maximum size limit, I attached it as a link: