I've asked how fragments, pixels, samples etc. relate to eachother. Notwithstanding, I'm positive that Chapter 14 can not be understood.

Chapter 14 starts with stating that the window coordinates span an integer grid, each rectangle along with its depth and shader output parameters is called a fragment.

This alone doesn't make sense (or disagrees with what's intended). The rectangle is unique, the parameters are not. Correctly, it should be "A reference to a rectangle along with ... is called a fragment". Otherwise "producing fragments" makes no sense.

14.3. then defines a "fragment square" without any meaning whatsoever.

14.3.1 refers to a process called "sampling" without any clear definition, whatsoever. Similarly, there is notion of "resolving to a single color each time a pixel is updated". Both, resolving and updating a pixel are not defined. For what it's worth, pixel isn't defined at all. It goes on with "pixel sample values" which has no meaning, followed by "sample" and "pixel fragment". I'll stop at this point because it should be obvious that the secion is completely incomprehensible.