Well, I've actually used them in speech; we were putting a group together (it later became Ben Borscht and the Beats, of Clifftop fame ((??!!)) but was first named Otter Chaos. But i digress. We had four members, and I said something like "I don't think we'll have any trouble finding material; the set A intersection B intersection C intersection D should have lots of members" and everybody knew just what I meant.