.square, .circle{
   Width: 100px;
    height: 100px;
}
.circle. {
    border-radius:50%;
}
#blockpowderblue  {
    background-color:powderblue;
}
#container{
    background-color:mediumpurple;
    margin:0 auto;
    width:400px;
    height:400px
}
#blockhotpink {
     background-color: hotpink;
}