>
        <header>
          <h1>Composition</h1>
        </header>
        <h2 id="overview">Overview</h2>


        <p>The ease by which other <em>people</em> can read and understand a program (often
          called "readability" in software engineering) is perhaps the most important
          quality of a program. Readable programs are used and extended by others,
          sometimes for decades. For this reason, we often repeat in CS 61A that programs
          are written to be read by humans, and onl