Type: Test of Disorder.
Description: A tall water filled room that guards an artifact or other important object.

This is a large vertical room 25 levels high and is filled with water that reaches the bottom of level 25. The objective is on level zero. Drainage grates connected to pumping systems control the water level. However there are 3 metal iris doors that block access to level zero. These doors have small holes to allow water to pass through them but nothing else and there is no way to force them open or breach them. Each one is powered by a control panel located on a specific level. However you cannot see which levels these are.

Don't even think of trying to use water breathing magic and/or swimming. The security system has electrified the water and touching it will result in a lethal shock. Also an Anti-Magic Field encompasses the whole room. Even if you bypass that, those iris doors still block the way. The control panels for the iris doors are disabled while the room has water in it.

To access level zero you need to lower the water level completely. You can do this with a control panel at the top which allows you to lower it by 1, 3, or 4 levels at a time. The security system can also lower the water level by the same intervals. You and the security system will take turns lowering the water level by one of the three options.

The security system is programmed to make its move only after you make yours.
It is not possible to lower the water level below level zero.
If the next move the security system can make in its turn lowers the water to level zero, then the control panels to the iris doors will remain disabled and you will have to start over.
If the next move you can make in your turn lowers the water to level zero, the control panels will activate allowing you to open the iris doors granting access to level zero and the objective.
The security system will always choose the best possible option on its turn.
You are the first to lower the water level.

This is how the levels are laid out:
LEVEL-24 <-- Water starts at the top of this level.
LEVEL-01 <-- Iris Doors at the bottom of this level.
LEVEL-00 <-- Objective is at this level.

Solution: Since you start the puzzle by lowering the water level first, you need to lower it to level 21. In subsequent turns you then need to lower the water to levels 16, 14, 09, 07, 02, and 00. This forces the security system to allow you to lower the water level to zero on your turn. This is because both you and the security system can only lower the water level by 1, 3, or 4 levels at a time.

You might want to give the players a hint by telling them to lower the water to level 21 first if they cannot figure out the logic in the puzzle.