Robert Scholes once affirmed that the sense of design is
 essential to a full reading experience and that in fiction it takes
 many forms. which are mainly of two kinds: juxtaposition and
 repetition. I If so one of the very causes of difficulty in "Ping". 
 its repetitive nature and its elusive permutations. https://herbsdailyes.shop/product-category/laboratory-glassware-and-plasticware-microscope-slides/