<span class="Keyword">object</span>
  <span class="Identifier">buffer</span><span class="Other">:</span> <span class="Identifier">seq</span><span class="Other">[</span><span class="Identifier">T</span><span class="Other">]</span>
  <span class="Identifier">headA</span><span class="Other">,</span> <span class="Identifier">headB</span><span class="Other">:</span> <span class="Identifier">int</span>
  <span class="Identifier">tailA</span><span class="Other">,</span> <span class="Identifier">tailB</span><span c