#container {
    background-color: white; margin: 0 auto;
    width: 800px;
    height: 800px;
}
.square {
    width: 400px;
    height: 400px;
    display: block;
    float: left;
}

.rectangle {
    width: 150px;
    height: 32px;
    display: block;
    float:none;
}


#blockBlue {

    background-color: #3a3082;
    position: relative;
}

#blockRed {

    background-color: #e0422d;
    position: relative;
}