The square symbols on the bell's four sides are numbers (1, 3, 6, and 10) that represent the amount of times to ring each side. Any order should work. The bell disappears forever, replaced by an anticube.
In the waterfall room, enter the tetromino code on the pillar to open a door beneath the waterfall. The valve in this room lowers the water across the first warp zone. This is unrelated to the moon door.
Solution:
Enter this code anywhere in the room: ← LT → RT ↑ A ↓ RT RT.
Best Answer
This is the 64 cube pyramid, to lower the water you need to go to the crying face waterfall and enter the tetromino code.
How do you lower the water in the lighthouse area and main warp room?