While the "index of" method was popular in the early 2000s, it is no longer the best—or safest—way to get updated subtitles.
The most iconic element of the season is Michael’s full-body tattoo. It serves as a literal and metaphorical blueprint. Visually, it is a gothic masterpiece of imagery; functionally, it hides the prison's blueprints and various escape codes in plain sight. This plot device allowed the show to maintain a procedural element within a serialized story. Each episode often focused on "obtaining" a specific piece of the puzzle—a key, a chemical, or a person’s trust—using the tattoo as the guide.