Detect two or more UIButtons being pressed at the same time
<p>I have three <code>UIButtons</code> on a storyboard.</p>

<p>What is the most straightforward way to detect when:</p>

<ul>
<li>two of the <code>UIButtons</code> are being pressed at the same time?</li>
</ul>

<p>or</p>

<ul>
<li>three of the <code>UIButtons</code> are being pressed at the same time?</li>
</ul>