Hollow

Template:PuzzleInfobox Hollow is the gold puzzle in the Anthropic Hills area of The Talos Principle 2.

Overview

On entering the puzzle, you find that there is a room on the left gated by a purple barrier, a room next to it gated by a plasma door, and a corridoor to the right blocked by 3 plasma doors that leads to the progress wheel. In the left room is a red activator, an RGB converter, and a swapper with a connector in it. In the second room is a green activator and a blue emitter. There is a red emitter outside.

Hints

A basic hint:

[ hint ]

There are at least three tricky stages to this puzzle, and some people consider this to be in the top-3 hardest puzzles of the base game. The name of the puzzle isn't much of a help. Try to think logically what the end state of the puzzle should be - what equipment you will need at the very end, and in which rooms. Proceed from there.

If you want to know the first objective you have to complete:

[ hint ]

Your first job is to move the red activator to the second room.

If you read the first objective above and need a hint on how to do it:

[ hint ]

First, bring the green activator out to the first room. Now put away the connector in the swapper, this will give you access to all the tools you need.

If you want to know the second objective you have to complete:

[ hint ]

Your second job is to make the red activator self-sustaining, but positioned so that it can activate other equipment.

If you read the second objective above and need a hint on how to do it:

[ hint ]

You might think that you can put the activator close to the plasma door, connected directly to the red emitter, and then jump start it from the other room with a connector, but you're skipping a step. You will need to do that, but before you do, you also need the green activator in the second room so that you can retain mobility between the two rooms.

If you want to know the third objective you have to complete:

[ hint ]

Your third job is to get the connector and RGB convertor out into the open while still keeping the plasma door activated so that the blue emitter is accessible.

If you read the third objective above and need a hint on how to do it:

[ hint ]

It might have been a while since you solved activator puzzles, so recall that activators can activate other activators. Use that idea. Bring the connector out into the open first, and see if you can aim it into the second room via the purple barrier and the window from outside. You may have to play with the angles a bit.

Story

On solving this puzzle, we hear another set of lines in the story:

Everything you see around you is Athena. Her hopes and fears superimposed onto the landscape of our island. And hidden behind the most difficult trials is precisely the device I need access to. You see, I don't think it's a coincidence that her mind picked Pandora as one of its avatars. On some level she knows I might be right.
But grief is something we cling to. We get used to it. We start being afraid of letting it go, because what if we try, and we're disappointed? That seems too much to take, so we put up walls around the very idea of trying. That's why she picked Pandora. That's why she hid this all away. Because left at the bottom of that box ... was hope.

—Cornelius (3)