Superliminal has various hidden (literal) Easter Eggs, and according to various online walkthrough there is one in the 'Labyrinth' section that is hard to reach. I reached the area in question but found no egg there. However, since my method was much easier than others I found, here is what I did.

I made the green staircase nice and big on the opposite side of the room. The corridor we are aiming for is on the wall behind me.

How do we make the staicase this big without the floor collapsing? The floor is supported by two beams, and the trick is to grow the staircase while keeping it centred above one of the those beams. If the floor tile you're on starts to tip then quickly pick the staircase up again and recentre it.

Unfortunately, these beams run parallel to our target corridor, and we need to be more central in the room in order to see into the corridor. Eventually, though, the staircase will be big enough that it can straddle both of the supporting beams and hence be oriented perpendicular to the corridor.

This allows us to climb the staircase and see into the corridor. In the following picture, a simple jump lets me grab the cube.

I climbed the silly cube steps I'd made and reached the corridor, but there was no egg there! Maybe it was removed for the PS4? If so, it's a bit of a shame. But I don't mind, as the achievement of reaching the corridor was reward in itself.

Lastly, a view of the green staircase from the corridor.