Carmack said he considers the prospects for the upcoming physics acceleration chip on the PC iffy, because physics presents a very fundamental problem that graphics doesn't have: it isn't easily scalable for level of detail. Either an object in the game is a true physics object with which other objects can interact, or it isn't. Carmack predicted this constraint would lead to a number of physics-accelerated titles where acceleration affects only elements, such as flowing water, that are peripheral to the core gameplay experience.