The Vedanta Sutras, commentary by Sankaracharya (SBE34), tr. by George Thibaut  at sacred-texts.com
19. And like a piece of cloth.
As of a folded piece of cloth we do not know clearly whether it is a piece of cloth or some other thing, while on its being unfolded it becomes manifest that the folded thing was a piece of cloth; and as, so long as it is folded, we perhaps know that it is a piece of cloth but not of what definite length and width it is, while on its being unfolded we know these particulars, and at the same time that the cloth is not different from the folded object; in the same way an effect, such as a piece of cloth, is non-manifest as long as it exists in its causes, i. e. the threads, &c. merely, while it becomes manifest and is clearly apprehended in consequence of the operations of shuttle, loom, weaver, and so on.--Applying this instance of the piece of cloth, first folded and then unfolded, to the general case of cause and effect, we conclude that the latter is non-different from the former.