body{width:800px;}

​

#wrapper{position:relative;}

​

#blue{

    float:left;

    height:225px;

    width:520px;

    background:blue;

}

​

#yellow1,#yellow2{

position:relative;

width:250px;

height:200px;

margin:10px 0 20px 540px;

background:yellow;}

​

#red{

  background:red;

  position:absolute;

  height:200px;

  width:520px;

  top:200;

}