I guess the idea is that all the strength comes from the shell, but those posts look pretty flimsy. Is their purpose mainly to be a template for the creation of the floor, which in the end is held up by the sides? (Confession: I could only watch two episodes ... even though I had read enough of the comments to know he didn't die in one of the videos, it was creepy watching his feet slipping on beams so far above a concrete head smasher.)