main {
    display: flex;
    justify-content: center;
    align-items: center;
    height: 100vh;
    background-color: white;
}

main div {
    background-color: green;
    width: 50px;
    height: 200px;
    margin: 10px;
    border-radius: 50px;
    animation: load 2s ease-in-out infinite alternate;
}

main div:nth-child(1),
main div:nth-child(5) {
    animation-delay: 0s;
}

main div:nth-child(2),
main div:nth-child(4) {
    animation-delay: 0.2s;
}

main div:nth-child(3) {
    animation-delay: 0.4s;
}

@keyframes load {
    0% {height: 50px;}
    50% {height: 200px;}
    100% {height: 50px;}
}