What triggers the missing yellow sigil in the Talos Principle?
I've already finished the Talos Principle (at least up to the second ending), but my friend hasn't, so we've been comparing notes. I remember in my play through that I was missing a yellow sigil for the platform, and that Elohim eventually reset a beginner yellow puzzle so I could complete it again, thus gaining the final sigil. Yet my friend says that this never happened to him. What could have triggered this for me, but not for my friend? And is there some extra yellow puzzle that my friend has done and I haven't or something? What accounts for the extra yellow piece?
Edit
To clarify, Elohim explicitly stated something along the lines of "I'm going to reaffirm your faith in me, so let me reset this puzzle for you so you can do it again." I wasn't in a puzzle when he said this, and it wasn't the usual why-not-take-a-break-from-this-puzzle thing that he does. Additionally, there was a QR code message from Sheep stating that he was in the same predicament.
Has anyone experienced this sort of thing besides me? I played it a while ago, but still, I have a really vivid memory of this. I'm very hesitant to think this is just something I imagined.
Edit Edit
Oh, and it would be great if anyone who has had this experience themselves comments about it, so I know I'm not crazy.
The mentioned QR-code is indeed in the game as:
I don't have enough yellow sigils for the device I need! This is crazy!
-- Sheep v69.1.0702
After digging through the game file, I cannot find the voiceover file that you mentioned. I also can't find any mention of this in the script files, but not everything seems to be in readable lua files. What I do know is that there is no way to "finish" a level without picking up the sigil. Solving the puzzle and then exiting without picking up the sigil will just be recorded as a "puzzle exit" event, which means that the sigil will be there even after reloading the world.
There are 9 yellow sigils in levels A-1 to A-4, and 14 yellow sigils in levels B-1 to B-7. That makes a total of 23 sigils.
There are exactly 23 sigils needed to unlock all items as shown in the following sigil puzzle solutions. You can access all previous puzzles. There is even a way to get back in the tutorial area if you are quick about it.
(source: https://www.gamefaqs.com/pc/805905-the-talos-principle/faqs/70787?page=3)
While thinking about this there might be one other problem: You unlocked the items in the "wrong" order, preventing you from completing the other yellow puzzles. The yellow puzzles you could not complete should however not be crossed out.
- A1: No requirements for 2 sigils
- A2: No requirements for 1 sigil
- A3: No requirements for 2 sigils
- A4: Connector for 4 sigils
- B1: Connector for 3 sigils, Hex for 2 sigils
- B2: Fan + hex for 1 sigil, Connector for 1 sigil, Fan + hex + connector for 1 sigil
- B3: Fan + hex for 1 sigil, Fan + hex + connector for 1 sigil
- B6: Connector for 2 sigils
- B7: Connector for 1 sigil, Hex for 1 sigil
You get 5 sigils for free. If you spend 3 sigils on the connector, do all 10 sigil puzzles with the connector, then "buy" the fan and the recorder, you end up with 2 sigils and no more yellow puzzles you can complete. I am not sure if this is possible, because I am not sure if you can access World B without access to the hexahedron. Still, if there is a way to trigger this message, then this is the most likely theory how to do it. Another way might be by buying the platform before the fan, locking you out of 4 puzzles. Again, I am not sure if you can access World C without buying the fan.
(Made with: http://madebyevan.com/fsm/)
In all likelihood, you finished an early puzzle but never collected the sigil. Collecting the sigil is what counts as solving the puzzle. I've never seen a puzzle reset automatically, but I imagine you solved it once, left without the sigil, came back, and the puzzle was unsolvable. The game probably gave you a reasonable amount of time to reset manually, but it presumably decided you weren't going to do that.