See the giant huge completely obvious problem? This cardigan is constructed by first knitting the lace back in the round. Then, because the lace doesn't cover your whole back, you knit two strips to go on top and bottom of the lace to fill out the length of the back. These strips are seamed to the top and bottom of the lace (as you can see, I haven't sewn the seams yet.) Then you put live stitches from the side on one long needle and knit the sides of the sweater out horizontally. The sleeves are put in as afterthoughts, just like you would an afterthought heel. Here's the top back of the sweater:
No problem there, just need to sew the seem. Here's the bottom back of the sweater.
Yeah. Oops. Turns out, when I attached the strip that borders the bottom of the lace, I twisted it 180 degrees. I made it a mobius. Since my back is not a mobius, this is definitely a problem. I can't think of any solution other than ripping the side back to wear I attached the strip. Hundreds of stitches and the set up for the afterthought sleeve all in vain.
Because I don't want to deal with this obvious problem, I'm knitting the sleeve on the "good" side of the sweater. Clearly I will have to do something about this eventually, but for now I'm just kicking myself and moving along like nothing is wrong.