Untitled

<!DOCTYPE html>
<html>
    <head>
        <title>Square Game</title>
    </head>
    <body>
        <input type="button" value="Start" id="startbutton">

        <div class="box yin-yang yin-yang:before yin-yang:after" id="one">
        </div>
        <div class="box yin-yang yin-yang:before yin-yang:after" id="two">
        </div>
        <div class="box yin-yang yin-yang:before yin-yang:after" id="three">
        </div>
        <div class="box yin-yang yin-yang:before yin-yang:after" id="four">
        </div>
    </body>
</html>