em> of the program.  We say that the program <em>halts</em> at that point.  (Please note that <em>halt</em> is an important technical term which we explain <a class="reference internal" href="haltDef.html"><span class="doc std std-doc">in a different notebook</span></a>.)</p>
<p>If the first symbol of R2 is a <code class="docutils literal notranslate"><span class="pre">1</span></code>, then the second instruction after the case instruction at the top transfers us down to line 6. This part of the program wou