While Oreo cream may not appear to possess fluid-like properties, it is considered a "yield stress fluid"—a soft solid when unperturbed that can start to flow under enough stress... Curious as to whether other had explored the connection between Oreos and rheology, Owens found mention of a 2016 Princeton University study in which physicists first reported that indeed, when twisting Oreos by hand, the cream almost always came off on one wafer.