*{margin:0;padding:o;}
#box{margin:50px auto;width:800px;height:800px;border: 2px solid black}
#content{width:100%;height:800px;}


/** layout 1  **/
#layout #content1{width:50%;height:400px;background:orange;float:left;}
#layout #content2{width:50%;height:400px;background:cyan;float:left;}
#layout #content3{width:50%;height:400px;background:green;float:left;}
#layout #content4{width:50%;height:400px;background:pink;float:left;}


/** layout 2  **/
/** layout 3  **/