If you're talking to someone you suspect may be a visual thinker, and they're not getting your point from your telling stories, you could try drawing a picture. If they now get it, that reinforces your belief that this clustering is meaningful, that they belong in that category, and it gets your point across. If they still don't get it, that accredits the hypothesis that your point is unclear, or that they are yet another type of thinker. ;)