ass="highlight"><pre><span></span><span class="n">ud</span> <span class="o">=</span> <span class="n">p</span><span class="o">::</span><span class="n">class_</span><span class="o">&lt;</span><span class="n">BinarySquare</span><span class="p">,</span> <span class="n">boost</span><span class="o">::</span><span class="n">shared_ptr</span><span class="o">&lt;</span><span class="n">BinarySquare</span><span class="o">&gt;</span> <span class="o">&gt;</span><span class="p">(</span><span class="s">&quot;BinarySquare&