Section 3.3 Blocks
Besides paragraphs (Section 3.2) the most common object to include in a division is what we informally refer to as a block. These are self-contained units of text, almost always set-off visually, and likely with a number and a title. If you know LaTeX, you may be in the habit of calling these environments. Mathematical results are one example, and you can start at Section 3.20 to learn more. There are others that are more general-purpose, such as
<remark> and <example>. While fundamentally different from these blocks that are textual with reflowable lines, objects like <figure> and <table> (Section 3.13) or <program> and <console> (Section 3.10) are blocks, even if their contents are more rigid or spatial. For a more precise description, see Section 4.2.
