body {
    margin: 0;
    height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    overflow: hidden;
}

.frame {
    width: 100vmin;
    height: 100vmin;
    background-color: whitesmoke;
    position: relative;
    perspective: 40vmin;
}

.wall {
    overflow: hidden;
    transform-origin: 0 0;
    position: absolute;
    width: 100%;
    font-size: 75vmin;
    font-weight: bold;
}

.wall.top {
    transform: rotate(0deg) rotateX(-90deg);
    top: 0;
    left: 0;
}

.wall.right {
    transform: rotate(90deg) rotateX(-90deg);
    top: 0;
    left: 100%;
}

.wall.bottom {
    transform: rotate(180deg) rotateX(-90deg);
    top: 100%;
    left: 100%;
}

.wall.left {
    transform: rotate(270deg) rotateX(-90deg);
    top: 100%;
    left: 0;
}