Answer:
Any piece of writing is shaped by external factors before the first word is ever set down on the page. These factors are referred to as the rhetorical situation, or rhetorical context, and are often presented in the form of a pyramid.
Drawing of three two-sided arrows in the shape of a pyramid. Where points meet on top, "Purpose"; bottom left, "Author"; bottom right, "Audience." "Message" is in the middle.
The three key factors–purpose, author, and audience–all work together to influence what the text itself says, and how it says it. Let’s examine each of the three in more detail.