Originally Posted by Ian Goddard

And even in the case of a grid with known edges (such as a checker board) there can be noncentral expansion. In short, there are two things at hand: (1) a center of an area and (2) a center of an expansion. If there is 1 and expansion is occurring, there is not necessarily 2. If a whole object uniformly inflates where each subregion inflates to the same degree as all others, the inflation has no center, ie, no point on the object around which or from which the inflation is uniquely radiating -- the inflation is originating from everywhere in the object.