![](http://www.smashbros.com/en_us/gamemode/various/images/various10/various10_071029c.jpg)
![](http://www.smashbros.com/en_us/gamemode/various/images/various10/various10_071029f.jpg)
Notice that the structure parts are completley different. I think this means that parts are unlockable, or not every structure has been put in yet. We could also have different structures for different backgrounds, but that would be stupid, and I don't see it happening.
We can also see that conveyor belts are not on the structure list.