Crypt Puzzle

The Crypt Puzzle refers to the sequence of doors you must enter in the Crypt in order to reach the Tree of Death and obtain the Skull Artifact.

The sequence is revealed by obtaining the four treasure maps and knowing how the counting system in FEZ works.

The doors on the maps are numbered, which reveals the order you must travel in.

Speculation & Interpretation

The Crypt Puzzle is possibly a reference to the Lost Woods from the original Legend of Zelda for NES, which has reappeared in many sequels in the series. Which requires a secret sequence of directions to travel in. Gomez has a poster from the Legend of Zelda for NES in his room, and Phil Fish cited it as an inspiration for FEZ in Indie Game the Movie.