By Kagen Schaefer, a guy who evidently likes to play with his wood.
Front:
Back:
Organ pipes.
Air connectors connect from the small drawers in the back of the desk to the organ pipes in the front of the desk.
The pnumatic logic board. This is an air powered computer.
It reads eight different sources of airflow which enter through the pipes on the top.
The screws are adjusted to program the computer to accept any sequence, or tune.
When the correct tune is played, air is allowed into this mechanism called the pendulum lock.
This triggers a secret part of the desk to open up.
All large drawers have puzzles inside.
You will need to solve these puzzles to open other drawers or find secret compartments.
Unlocked and open desk.
Source.
When you push in a drawer on the desk the air is directed to one of the organ pipes at the front of the desk, sounding a note. Some of the air is also directed into a pneumatic logic board. The logic board within the desk actually keeps track of the notes played. When it picks up the correct tune it unlocks a very special secret compartment. The logic board, can be reprogrammed to pick up any tune, so at any time the song may be changed to a new tune. It is powered entirely by air, and it is made entirely from solid wood.
Front:

Back:


Organ pipes.

Air connectors connect from the small drawers in the back of the desk to the organ pipes in the front of the desk.

The pnumatic logic board. This is an air powered computer.
It reads eight different sources of airflow which enter through the pipes on the top.
The screws are adjusted to program the computer to accept any sequence, or tune.

When the correct tune is played, air is allowed into this mechanism called the pendulum lock.
This triggers a secret part of the desk to open up.

All large drawers have puzzles inside.
You will need to solve these puzzles to open other drawers or find secret compartments.

Unlocked and open desk.
Source.