.square, .circle {
            width: 200px;
            height: 200px;
            display: block;
            position: relative;
            }
            
            #container {
                background-color: blue; margin: 0 auto;
                width: 400px;
                height: 400px;
                }

                #blockRed {
                    background-color: rgb(232, 4, 4);
                    position: relative;
                    }
                    #blockBlue {
                    background-color: rgb(69, 14, 235);
                    position: relative;
                    }