What is sticking out of the roof?

[Micke_xyz]

 

[Demmpa]

A little more info is needed

Metal/plastic?
What is on the floor above?
Close-ups?
Where are they in relation to each other?
What spaces are they in?

Can the cover plates at the bottom be removed?
What does it look like inside?

 

[Micke_xyz]

A little more info needed

Metal/plastic?
What's on the floor above?
Close-ups?
Where are they in relation to each other?
What kind of spaces are they in?

Can the covers at the bottom be removed?
What does it look like inside?

Forgot the description.

They're in a hallway 2 meters from each other. They feel very hollow and loosely attached/fragile. They may have a cover, but they are painted over, so it's hard to say. I don't dare to fiddle with them too much because it doesn't seem like they can be put back if they come loose. There's only a hallway on the floor above where they are located.