g>led (ring, x, val)</strong>
    </dt>
    <dd>
    set state of single LED on this arc device.


    <h3>Parameters:</h3>
    <ul>
        <li><span class="parameter">ring</span>
            <span class="types"><span class="type">integer</span></span>
         : ring index (1-based!)
        </li>
        <li><span class="parameter">x</span>
            <span class="types"><span class="type">integer</span></span>
         : led index (1-based!)
        </li>
        <li><span class="parameter">val</span>
