WOW that is what I have to say about Codex. It is amazing in every way - one of the most sincere and beautiful Radiohead songs I can remember. After listening to The King of Limbs now 3 times this morning - this song would always seem to bring me in the most. The piano sound is gorgeous and mixed with Thom's incredible vocals it helps create a very engaging and powerful tune.
I love that they put this song right in the middle of the other two power house tunes from TKOL (Lotus Flower and Give Up The Ghost). Codex is such a chill laid back tune but at the same time it is so powerful and moving. For me this is my clear cut favourite song on The King of Limbs. And man I really wish that 8 songs was more like 12 songs. Great great album nonetheless though and I suspect that when it gets its physical release they will be adding another disk or some more songs.
THANK YOU RADIOHEAD!