This is kind of a weird idea, but would it be possible to make a small biome that generates with a big wall around it?

sometingh like hasbeen done before

 

[redacted - please use proper links to the mods, not scam sites like 9minecraft]

 

in my head i have a vision of how to doid but you need to make code to detec the biome bounds and borders and create the wall 

You can set biomes up to have a border biome, like how ExtremeHills has ExtremeHillsEdge or used to, so you can have your Biome, and have a border biome that either you generate the extra blocks on or just have the altitude of the biome a little higher to give the appearance of a wall.

What was that mod supposed to be? Because 9minecraft is gross