0052"></a><span class="lineno">   52</span>&#160;<span class="keyword">template</span> &lt;</div><div class="line"><a name="l00054"></a><span class="lineno">   54</span>&#160;  <span class="keyword">typename</span> Shape_,</div><div class="line"><a name="l00056"></a><span class="lineno">   56</span>&#160;  <span class="comment">//  (concept: ReadableTileIterator | ForwardTileIterator | MaskedTileIterator)</span></div><div class="line"><a name="l00057"></a><span class="lineno">   57</span>&#160;  <span class