mputeroutput"><span class="identifier">node_base</span><span class="special">*</span></code>
          and <code class="computeroutput"><span class="identifier">node_iterator</span></code> can be
          observed when they are incremented: <code class="computeroutput"><span class="identifier">node_iterator</span></code>
          follows the <code class="computeroutput"><span class="identifier">m_next</span></code> pointer,
          while <code class="computeroutput"><span class="identifier">node_base</s