Sentence:  In order to be saved , plasticity had had to be isolated ; and as the aspect of the subject was transposed into those clusters of more or less interchangeable and contour obliterating facet-planes by which plasticity was isolated under the Cubist method , the <WSD>subject</WSD> itself became largely unrecognizable . 
Meaning of the word marked with <WSD> tags:  something (a person or object or scene) selected by an artist or photographer for graphic representation