 You can see that this spine here is vertical, however, it's not perfectly straight. And what I mean by that is we have a curve here. We have another curve here going in the opposite direction. And then a third curve here again going in just the opposite direction. So it's kind of alternate. If you had a perfectly straight spine like a stack of blocks, what that would mean is all of the weight from the blocks on the top would be compressing all of their weight on the lower blocks. The curves allow it so that that weight is displaced, the weight is taken off of your body. Think of those curves that are acting kind of like a spring.