<div class="shape-ex2"></div>
.shape-ex2{
    width: 100px;
    height: 100px;
    background-color: #666;
    margin: 0 auto;
    animation: fadeOut 2s linear 0s infinite;
}
@keyframes fadeOut {
    from {
        opacity: 1;
    }
    to {
        opacity: 0;
    }
}

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