Dual dimension skull farm

ArcaneMC's dual dimension wither skeleton farm, built on a fortress with four crossroads and inspired by Elyrio3's design. The skeletons spawn on the crossroads in the nether and go through portals to be killed on the overworld side, with jCraft's sorters and a shulker box storage on the end. Because the two halves sit in different dimensions it needs two players, or a carpet bot on Fabric, to keep both loaded at once. The video is a 78 second showcase, so the schematics are the build instructions. Full rates also want the bedrock roof taken off above the whole farm and a perimeter dug out.

It is dual dimension, so it takes two players. On Fabric a carpet bot covers the second one, and a multiplayer server works too.
Maximum rates need the bedrock roof removed above every part of the farm and a perimeter dug. The creator puts that at around 100 hours of survival work, which he did himself.
Build it on the quad crossroads and nowhere else. Arcane_MC uses minihud bounding boxes to find them and a 128 block spawn sphere to pick the spot with the fewest spawnable blocks outside the farm.
Rates coming in low almost always mean the nether roof above the farm has not been removed yet.
Elyrio3 points out that wither skeletons now spawn up to light level 11, so the floating snow is no longer needed and putting portals straight around the piglins is easier.
joedoego's shulker sorter jammed on 1.21, with the items stuck in the hopper above the box. Nobody answered.