I have a little theory about Talfargar (Watever you write it) Law and his devil fruit.
People seem to believe his devil fruit controls space and can move certain objects or parts of it around a predetermined space. Well, my theory is similar but with a little difference.
Instead of being a space where everything can be moved, it would be more of a space where the user can "rotate" everything within that space. For example, when that cannon ball was shot at Law and he used his ability, he swaped the head ad the cannon ball's places, which could be possible with a rotation of the top of that room. The other thing that could prove this theory is the fact that the cannon ball, after Law had moved it, headed towards the marines. Basicly, if he just moved it, it would still follow his path, and Law cannot throw an object at that kind of speed even with his ability. Another proof that the area rotated.
Also, some people think it's more of a "swap" technique. Replaceing one object with another. But, once again with the cannon ball, if both the cannon ball and head would've swapped positions, the cannon ball would still continue it's way to Law.
So basicly, Law can rotate at will different parts of his "room". Which can also explain why some marines had many body parts on them while some random parts would be left alone.
Anway, it's just my little theory. I thought it made quite some sense so I decided to post it here.