Point at a cloud. How many separate 'clouds' did you actually just point at?

A cloud has no sharp edge: zoom in and there's no exact boundary where water vapour stops counting as part of it, so countless very slightly different clumps of molecules each have an equal claim to being 'the cloud'. If none of those near-identical candidates is privileged over the others, there seem to be many clouds occupying almost the same space, yet you were only looking at one thing. Philosopher Peter Unger used the puzzle to argue vague objects may not strictly exist as we assume.

— Peter Unger, The Problem of the Many — Midwest Studies in Philosophy, Vol. 5, 1980