Anodunos dam control puzzle

The Anodunos dam control puzzle in Ultima Underworld II can be a difficult task to solve, especially since the hints given are rather cryptic and not even complete. The goal in the puzzle is to re-arrange a labyrinth to first free the way to a key and then re-arrange it again so that the Avatar can reach the door in which the key fits, so that the hero can pull a lever to free the way to the city of Anodunos.

The dam controls to change the labyrinth consist of a chain that can be up or down, a switch and a lever which can be up or down, and a button that can be pushed (dark) or released (light). The only hint is an incomplete message found on the floor. The original message reads:

Step-by step solution:

• To reach the key, the chain, lever and switch must be all in the up-position and the button released (light). Chain-up, Switch-Up, Lever-up, Button-light
• Now get the key from the labyrinth.
• Return to the controls. Now push the switch and lever down, but keep away from the chain. Push the button (dark). Chain-up, Switch-down, Lever-down, Button-dark
• Now you can reach the door and unlock it to get to the floodgate control chain. Pull it.