 Cumulativity may be a more dogged criterion, as it is relatively consistent for two (+COUNT/-MASS) N’s not to be an N, e.g. two people don’t seem to be a person, whereas some (-COUNT/+MASS) N and some other N are N, e.g. two bits of water are water. But there are many counterexamples to this as well. If there is an aggregate of well-demarcated individuals, then the aggregation of it with another yields an aggregate. Two connected but discrete planes can compose a plane, and some robots could be made to, Voltron-style, compose a robot. Or, less exotically, in certain circumstances two fleets or armies could compose a fleet or army. Granted, these are somewhat artificial examples, and cumulativity does seem to be much more common in +MASS than +COUNT, but it is not distinguished in this from +PLURAL. (See Sections  2.3  and  3.1  for accounts which reduce mass reference to plural reference).