body {
    margin: 0;
    padding: 0;
    background: #202020;
}


.container {
    position: absolute;
    left: 50%;
    top: 50%;
    transform: translate(-50%, -50%);
    width: 60px;
    height: 60px;
}

.box {
    position: absolute;
    width: 30px;
    height: 30px;
    background: #e74c3c;
}

.box:nth-child(1) {
    animation: a1 2s infinite linear;
}

.box:nth-child(2) {
    animation: a2 2s infinite linear;
}


@keyframes a1 {
    0% {
        top: 0;
        left: 0;
        width: 30px;
        height: 30px;
    }
    12.5% {
        top: 0;
        left: 0;
        width: 60px;
        height: 30px;
    }
    25% {
        top: 0;
        left: 0;
        width: 60px;
        height: 30px;
    }
    37.5% {
        top: 0;
        left: 30px;
        width: 30px;
        height: 30px;
    }
    50% {
        top: 0;
        left: 30px;
        width: 30px;
        height: 30px;
    }
    62.5% {
        top: 0;
        left: 30px;
        width: 30px;
        height: 60px;
    }
    75% {
        top: 0;
        left: 30px;
        width: 30px;
        height: 60px;
    }
    87.5% {
        top: 30px;
        left: 30px;
        width: 30px;
        height: 30px;
    }
    100% {
        top: 30px;
        left: 30px;
        width: 30px;
        height: 30px;
    }
}

@keyframes a2 {
    0% {
        right: 0;
        bottom: 0;
        width: 30px;
        height: 30px;
    }
    12.5% {
        right: 0;
        bottom: 0;
        width: 30px;
        height: 30px;
    }
    25% {
        right: 0;
        bottom: 0;
        width: 60px;
        height: 30px;
    }
    37.5% {
        right: 0;
        bottom: 0;
        width: 60px;
        height: 30px;
    }
    50% {
        right: 30px;
        bottom: 0;
        width: 30px;
        height: 30px;
    }
    62.5% {
        right: 30px;
        bottom: 0;
        width: 30px;
        height: 30px;
    }
    75% {
        right: 30px;
        bottom: 0;
        width: 30px;
        height: 60px;
    }
    87.5% {
        right: 30px;
        bottom: 0;
        width: 30px;
        height: 60px;
    }
    100% {
        right: 30px;
        bottom: 30px;
        width: 30px;
        height: 30px;
    }
}