Takes in two full space belts, outputs 2 full belts of the swapped shape, left half of the left input and right half of the right input.
Only works on homogenous shapes. If you plug in mixed shapes, eg ABCD to swap with EFGH, you're going to get sushi. Does not preserve lanes. Merges the outputs of the swappers, so it can't jam. Works equally if you don't have the 3rd layer unlocked, if you paste this into a 2-layer game it will work with just two floors.
Tons of room for additions and variants, if you want. It must be on the 4x2 platforms in order to fit enough input and output notches, so it's got room to spare.
