Sextus Empiricus Pyrrhoniae Hypotyposes 3.20.154

[154] For they say that it is from these that the rest of the numbers are generated—those, that is, which are involved in the perception of numerables—and the Universe is arranged. For the point presents the relation, or character, of the Monad, ¹ and the line that of the Dyad (it being regarded as lying between two points), and the surface that of the Triad (for they describe it as a flowing of the line breadth-wise up to another point placed transversely), and the solid body that of the Tetrad; for Body is formed by an ascension of the surface up to a point placed above.