What is the secret to the classroom in the 8-cube door city in Fez?

The room is located in the 8-cube door city-esque place. It has 3 walls with chalkboards on them and one with a blue/green picture of what looks like it might be a map of the world. I can't figure out the puzzle any help?

You have to use the tetromino cipher on the chalkboard.

The answer:

or just press: ↑ ← RT A LT → A ↓, and an anticube will appear

For keyboard: Up arrow, Left arrow, D, Space, A, Right arrow, Space, Down arrow

The main blackboard (shown in Sean's answer) either teaches you about the tetris codes or it drops a hint about how the numbers work.

The same sequence is shown 3 times, each with a number next to it.

1 - the code as it appears on pillars (in that form on another wall)

2 - the code split out into its constituent tetris pieces

3 (shown as 1+2) - the code turned on its side how you should input it.

Another room teaches you how to input that code.

These three steps show you how to read the input code every time you see one of those vertical glyphs.

It's the code sequence on the wall. Each tetrimino (Tetris piece) corresponds to a different button on your gamepad. The answer to this specific one is Up, Left, Right trigger, A, Left trigger, Right, A, Down.