What is the meaning of the three dots in The Beginner's Guide?

My Research

I had a quick look around and it seems as though no one has really come up with a definitive answer.

It's all just speculations on forums and discussions about the game.

The creator of the game hasn't made a statement on the dots.

An idea that someone had:

https://steamcommunity.com/app/303210/discussions/0/490121928348490895/

My Idea

To me it looks like the developer added the dots in almost just to mess with people. See how far they would go to try and analyse and figure out what it all means but in actuality, its just 3 dots on a wall.

Summary

There is no answer to your question, the dots are up for interpretation from each individual player.

The key line explaining why the dots are in The Beginner's Guide comes in the final chapter, when Davey says

that he has no idea what the three dots mean, even though he's repeatedly asked Coda to explain them.

In universe,

we will never know what the three dots mean.

Out of universe, they were included to show how enigmatic Coda is and

how desperate Davey is to impose meaning on Coda's games. He has an explanation for all of Coda's other imagery (even though Coda outright refutes some of those meanings in his message at the end of The Tower) but still can't decide what he thinks the three dots mean and is driven a little crazy by his inability to do so.