#container{
    background-color: pink;
    margin: 0px auto;
    padding: 0px;
    width: 400px;
    height: 400px;
}
.square, .circle{
    width: 100px;
    height: 100px;
    display: inline-block;
    float: left;
}
.circle{
    border-radius: 50%;
}
#blockRed{
    background-color: rgb(135, 170, 239);
}
#blockYellow{
    background-color: rgb(211, 161, 250);
}
#blockWood{
    background-image: url(https://616pic.com/sucai/z26flqwpv.html);
}