#container {
    background-color: #f0f8ff; /* Light blue background color */
    margin: 0 auto;
    padding: 0;
    width: 400px;
    height: 400px;
}

.square, .circle {
    width: 100px;
    height: 100px;
    display: inline-block;
    float: left;
}

.circle {
    border-radius: 50%;
}

#blockRed {
    background-color: #007bff; /* Blue background color */
}

#blockYellow {
    background-color: #007bff; /* Blue background color */
}

#blockWood {
    background-image: url('https://images.pexels.com/photos/172276/pexels-photo-172276.jpeg');
    background-size: cover;
}

#blockBlue {
    background-color: #007bff; /* Blue background color */
}