.square, .circle {
    width: 100px;
    height: 100px;
    display: block;
    }


.circle {
    border-radius: 50%;
    }

    .square {
        position: relative;
    }

.blockred {
        background-color: rgb(249, 134, 134);
        position: relative;
        }

.blockyellow {
        background-color: rgb(240, 180, 236);
        position: relative;
        }
        
#container {
    
    background-color: rgb(202, 246, 194); margin: 0 auto;
        width: 400px;
        
        }