.circle1{
    height: 50px;
    width: 50px;
    background-color:blue;
    border-radius:50%;
    position: absolute;
    left: 600px;
    top: 300px;
    animation: one 1s ease-in-out 50ms infinite ;
}
@keyframes one{
    0%{top: 300px;}
    40%{top: 280px;}
    90%{top: 300px;}
    100%{top: 300px;}
}

.circle2{
    height: 50px;
    width: 50px;
    background-color:red;
    border-radius:50%;
    position: absolute;
    left: 675px;
    top: 300px;
    animation: two 1s ease-in-out 100ms infinite ;
}
@keyframes two{
    0%{top: 300px;}
    60%{top: 280px;}
    90%{top: 300px;}
    100%{top: 300px;}
}
.circle3{
    height: 50px;
    width: 50px;
    background-color:yellow;
    border-radius: 50%;
    position: absolute;
    left: 750px;
    top: 300px;
    animation: three 1s ease-in-out 150ms infinite ;
}
@keyframes three{
    0%{top: 300px;}
    60%{top: 280px;}
    90%{top: 300px;}
    100%{top: 300px;}
}
.circle4{
    height: 50px;
    width: 50px;
    background-color:green;
    border-radius: 50%;
    position: absolute;
    left: 825px;
    top: 300px;
    animation: four 1s ease-in-out 200ms infinite ;
}
@keyframes four{
    0%{top: 300px;}
    60%{top: 280px;}
    90%{top: 300px;}
    100%{top: 300px;}
}