Sentence:  "Quining" is what I called it in my book. (He certainly didn't call it that!) <WSD>Quining</WSD> is an operation that I define on any string of English. ... Here is an example of a <WSD>quined</WSD> phrase: "is a sentence with no subject" is a sentence with no subject. 
Meaning of the word marked with <WSD> tags:  To append something to a quotation of itself.