Profile Drafts - Susan Kesler-Simpson

I am trying to figure out the patterns in the book Creative Treadling with Overshot by Susan Kesler-Simpson. In most of the patterns, she uses profile draft letters A-D, but does not specify how the blocks correlate to the letters. I find her explanation of profile drafting almost impossible to understand.

My question is: she defines four blocks on page 8 (Figure 11). Is she saying that these four blocks will be standard for the full book? Or are they just an example?