function roundedCorners(classes, top_class) {
   var targets = $$(classes); 	      
   targets.each(function(original) {
     original.className = original.className + ' round_content'; 	      
     var round_outer = new Element('div', { className: top_class + ' round_outer' });
     var tr = new Element('div', { className: 'tr' });
     var tl = new Element('div', { className: 'tl' });
     var br = new Element('div', { className: 'br' });
     var bl = new Element('div', { className: 'bl' });
     original.parentNode.replaceChild(round_outer, original);

     tr.appendChild(tl);
     tr.appendChild(original);
     round_outer.appendChild(tr);
     br.appendChild(bl);
     round_outer.appendChild(br);
    });
 }