Steam banner photo unknown objects

[Rumsfield]

Looking closely at the banner photo of Factorio in the Steam library, there appear to be two yellow objects near a blue and yellow assembler. What are they? They're not part of the assembler sprites. They almost seem like vehicles, with one oriented east-to-west and the other rotated 45 degrees. Are they some sort of image artifact caused by composite layering of multiple image layers? Or some future entity not yet released? Or am I just missing something from the vanilla game?

[T-A-R]

You have a sharp eye. If you ask me they look like silo clamps.
Edit: better picture

[Deadlock989]

You have a sharp eye. If you ask me they look like silo clamps.
Edit: better picture

I think that's right. They're at the same angles as the two different clamp animations (08-rocket-silo-arms-back and 08-rocket-silo-arms-right). Maybe left over from hiding parts of the rocket silo to get the rocket lined up in shot?