deinput">        <span class="keyword">function</span> addClickToStack(obj, x, y)
            <span class="keyword">if</span> obj.indexOf(x, y) == -1
                obj.stack(end + 1, :) = [x, y];
            <span class="keyword">end</span>
        <span class="keyword">end</span>
</pre><h2>removeClickFromStack<a name="12"></a></h2><p>Removes an (<i>x</i>, <i>y</i>) from the stack.</p><p><b>Paramters</b></p><p><tt>x</tt>: x coordinate</p><p><tt>y</tt>: y coordinate</p><pre class="codeinput">        <span 