body {
    margin: 0;
    height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    background: radial-gradient(darkgreen, black);
}

.loader {
    width: 10em;
    height: 10em;
    font-size: 20px;
}

.loader::before,
.loader::after {
    content: '';
    position: absolute;
    width: 1em;
    height: 1em;
    background-color: currentColor;
    box-shadow:
        0 0, 2em 0, 4em 0, 6em 0,
        0 2em, 2em 2em, 4em 2em, 6em 2em,
        0 4em, 2em 4em, 4em 4em, 6em 4em,
        0 6em, 2em 6em, 4em 6em, 6em 6em;
    border-radius: 50%;
    animation: round 2s ease infinite;
}

.loader::before {
    color: gold;
}

.loader::after {
    color: dodgerblue;
    animation-delay: -1s;
}

@keyframes round {
    0% {
        transform: translateX(0) translateY(0);
    }

    25% {
        transform: translateX(3em) translateY(0);
    }

    50% {
        transform: translateX(3em) translateY(3em);
    }

    75% {
        transform: translateX(0) translateY(3em);
    }
}