I upgraded my logic thing to a 2-bit full adder
https://files.catbox.moe/8rb8o4.wad
inputs are two 2-bit numbers (a and b) plus carry in. output bits are the pens
to work around not having a good way to invert a signal, in the first stage I form not just the carry (the topmost three "lanes") but also its inverse (the thick lane below it)
I economize as much on pinkies as I feel I can get away with, without making the thing too slow
I discovered that pinkies won't turn a 64x64 corner as nicely as a 64x96 one, which is why the bottommost set of gates are shaped the way they are