#div1 {
    width: 100px;
    height: 100px;
    background: #9fc1ff;
    position: absolute;
    left: 600px;
    top: 150px;
}

#target1 {
    width: 1px;
    height: 300px;
    position: absolute;
    left: 100px;
    top: 50px;
    background: #000;
}

#target2 {
    width: 1px;
    height: 300px;
    position: absolute;
    left: 300px;
    top: 50px;
    background: #000;
}

#target3 {
    width: 1px;
    height: 300px;
    position: absolute;
    left: 500px;
    top: 50px;
    background: #000;
}

#target4 {
    width: 1px;
    height: 300px;
    position: absolute;
    left: 1000px;
    top: 50px;
    background: #000;
}