 host.attachShadow({mode: 'closed'});
var box11 = createBox('box11');
var box12 = createBox('box12');
var box13 = createBox('box13');
shadowRoot.appendChild(box11);
shadowRoot.appendChild(box12);
shadowRoot.appendChild(box13);

var nestedHost = document.createElement('div');
var nestedShadowRoot = nestedHost.attachShadow({mode: 'closed'});
var box21 = createBox('box21');
var box22 = createBox('box22');
var box23 = createBox('box23');
nestedShadowRoot.appendChild(box21);
nestedShadowRoot.appendChild(box22);
