Fez is no stranger to obscure puzzles. The game is absolutely littered with them, some more complicated than others.
You think the golden bell or ominous owl are difficult to solve? Try finding the elusive red cubes dispersed throughout the world.
(Fez spoilers ahead.)
If you finished Fez you will have seen the awesome, cute, funny, and weird kill screen. You'll also have gained access to New Game + that lets you travel back through the three-dimensional world for more puzzle solving, and you can even do so in first-person.
Certain rooms give you access to bonus cubes, locked and hidden under secrets. One room, the monolith room, is proving to be a fickle puzzle for gamers across the Internet to solve. Some alleged solutions have made their rounds across forums, but to no real success.
What the Internet has collectively discovered, though, is that there is a tome and it needs to be translated. The consensus seems to be that it translates to form PAEAEBUB, or some variation of these letters. This translation might hold at least part of the answer. From that translation, you can hopefully figure out a button combination (a common puzzle-solving method in Fez) to activate certain sections of the room. If you complete the pattern correctly, the theory goes, you'll be granted with the infamous red cube that all of our achievement-hunting hearts desire.
But it might be even more complicated than that. First-person view is essential to solving this puzzle, if only to see certain secrets in the room itself. But other secrets you might've uncovered in the game could also help. Maybe the perplexing owl will lend a hint to this even more perplexing room. You might have stumbled on a book of codes that could help in the solution. Maybe it's a reference to 2001: A Space Odyssey where sound emissions are the key. Maybe there are missing clues that aren't even in the game. Some Fez gamers are suggesting haikus and even reading the translations in 3D. For now, mostly theories and ideas are being tossed around amongst forum members. The point is, the forum contributors and perplexed players are willing to try anything at this point.
GameFAQs user halfrobo sums up many of the theories, which range from completely wacky to somewhat reasonable:
a) the third red cube is needed to complete a shape which looks VERY much like the kokoromi logo;
b) the authorial nature of the game, and the presence of the creator in the game, has already been referenced in the "security question" where half of the answer was half of "Polytron";
c) the key to the monolith is not found in the game according to treyher; therefore it must have something to do with the developer personally, the development groups they've been in, or the themes of the game (sacred geometry etc) or maybe released with the soundtrack;
d) we may be looking for a 7 or 8 letter word but with fewer than 8 different letters (probably 5) where the first two letters map to the same rotated-symbol-set in the game, and joshrholloway has provided us with a big set of possible English words;
e) something may have poked Gomez's eye out in the future, thus turning him into the eyepatch'd Geezer;
f) the 64-bit name of G-d, like other numerological / alphabetic names of god (the true pronunciation of the Tetragrammatron, etc) may be a forbidden name, one which "chokes the speaker" so that it may not be uttered. This could be why the parchment with the other half of the floor symbol in the monolith room has been burnt;
g) the monolith is very obviously NOT a cube, but a more elongated shape reminiscent of the 1:4:9 geometry of the 2001 monolith;
h) the values written on the chalkboard in old Zu are in two columns. Both columns involve only FIVE of the six digits (or die-faces) from 1-6 and add up to 33 (3 = trixel / 3rd dimension + doubled = tesseract/hypercube) — and 33 is also the age that both Jesus and John Belushi died;
i) the creator and designer of Fez is 33 or was at some point during the development of this game; he is said by many to LOOK like John Belushi but ACT like he believes himself to be Jesus;
h) the above facts remind me of one of the creator's pre-release tweets to the community, which I believe was later deleted (due to spoilers?!) but has been saved by several Fez fansites:
i) check out this photo of the designer/creator which was taken about six months prior: [here] and note what large capital letter he's standing under. This may be a clue, the first letter in the word;
In the midst of some seemingly trolling solutions found online, one group effort is born. Gamers are standing in the middle of the "1" square (only viewable in first-person mode) in the monolith room and inputing various codes for verification. If this brute force method is successful, participants will indicate so on the recently created website in the hopes that an answer will reveal itself by process of elimination.
The theories, speculation, and random solutions have gotten so out of control that one GiantBomb user came up with one that makes a jab at the utter confusion that is this puzzle:
"I heard if you save in the monolith room and then restart the game and select continue while holding the A button and then alternate between the left and right triggers six times the Black Monolith turns into Sub-Zero."
The pages and pages of online threads are almost as obscure as the puzzle itself. My head is still spinning, as I am sure everyone who is attempting to solve by permutation is right now.
Ultimately, that's the beauty of Fez. It brings groups of gamers together to solve obscure puzzles that seem to confound us all. And it asks us to solve puzzles using maths and by drawing out maps. Not many games will have you breaking out a notepad and pencil like Fez does.