body
{
    margin: 0;
    padding: 0;
    background: #bd2ae2;
    display: flex;
    align-items: center;
    justify-content: center;
    height: 100vh;
}
.loader
{
    width: 150px;
    height: 150px;
    position: relative;
}
span
{
    position: absolute;
    width: 50px;
    height: 50px;
    background-color:white;
    border-radius: 4px;
    animation: chase 2s linear infinite;

}
span:nth-child(2)
{
    animation-delay: 0.7s;
}
span:nth-child(1)
{
    animation-delay: 1.4s;
}


@keyframes chase
{
    0% {top: 0; left: 0;}

    12.5% { top: 0; left: 50%;}

    25% { top: 0; left: 50%;}

    37.5% { top: 50%; left: 50%;}

    50% { top: 50%; left: 50%;}

    62.5% { top: 50% ; left: 0;}

    75% { top: 50% ; left: 0;}

    82.5% { top: 0; left: 0;}

    100% { top: 0; left: 0;}
}