Some light hints that may point you in the right direction:
Hint 1
The assembly is a part of a larger machine.
Hint 2
Several assemblies are meant to move side by side in unison.
Hint 3
The square-ish shaped piece is plastic that will wear down and be replaced.
More of a "put all of this stuff together in one package" sorta machine. The wear piece does push something while riding in the tracks. Technically the tracks do have various depths, but that's not too important to the general function of the assembly.
There is no cam type function in the machine. The assembly is solidly attached to the bar that moves.
The bar is aluminum and the square ish piece on the left is low friction plastic.
Is this like a part of something off the marble machine x?
https://youtu.be/qjkIMxmSeIc
Is it playing music from a large drum? Haha
Lol, that's a no. It's for an industrial machine.
Does this push paper along a track or converor by its edge? For like a newspaper or something?
Spot on.
Answer
It's for pushing mail into an envelope. Three or four of them work in unison to push a stack of papers/inserts into an envelope.God damn. That's the hardest one I've seen in a long time. Very nice.
I figured it would be a tough one.
These are mail insertion machines I worked on for several months as a mechanic. It's a little blurry since that were moving, but here it is in action:
That's cool. Never seen anything like that. I love big industrial machines that exist only to recreate an action a single human can do easily lol