You will also need to have solved the second level, which gives you access to the ground level

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This one cannot be accessed until you've done some end-game related tasks, described in next hints (SPOILERS)

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You will need to have solved the first/highest level of the mountain

At least seven lasers must be lit

Solve all 3 catwalk puzzles (the walkways made of light) and you're halfway to solving this puzzle

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After opening the door to climb down into the mountain, you'll confront several panel puzzles that will lead you deeper. This environmental puzzle can be found after completing the second two large catwalk puzzles.

For this environmental puzzle, all you have to do is go to the lowest level of the main chamber and look up.

When you first arrive at ground level, one of the lower catwalks will be complete -- the blue one. (The yellow catwalk will be partially blocked by a platform underneath it).

After you solve the blue environmental puzzle, the yellow one is a little trickier. (See River SE #5.)

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If you are solving puzzles inside the main chamber of the mountain, you'll probably be able to guess how to find this one

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You really have to have gotten far into the game to find this one.

Specifically, you have to have gotten inside the Mountain.

Take a look at the position of this puzzle on the obelisk

Notice how the three on the bottom of this side are much further BENEATH the two above them

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Lower on an obelisk doesn't always mean that the puzzle is lower in altitude, but in this case... You'll have to enter the mountain and head downward in order to solve it.

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