Sentence:  For the illusion of depth created by the contrast between the affixed <WSD>material</WSD> and everything else gives way immediately to an illusion of forms in bas-relief , which gives way in turn , and with equal immediacy , to an illusion that seems to contain both - or neither . 
Meaning of the word marked with <WSD> tags:  artifact made by weaving or felting or knitting or crocheting natural or synthetic fibers