test.css

.bb, .bb::before, .bb::after {
	 position: absolute;
	 top: 0;
	 bottom: 0;
	 left: 0;
	 right: 0;
}
 .bb {
     width: 50%;
	 height: 100vh;
	 margin: auto;
	 background:  rgba(0, 0, 0, .1);
	 color: #69ffff;
	 box-shadow: inset 0 0 0 1px rgba(105, 255, 255, .5);
}
 .bb::before, .bb::after {
	 content: '';
	 z-index: -1;
	 margin: 5%;
	 box-shadow: inset 0 0 0 2px;
	 animation: clipMe 8s linear infinite;
}
 .bb::before {
	 animation-delay: -4s;
}
 .bb:hover::after, .bb:hover::before {
	 background-color: rgba(255, 0, 0, .3);
}

@keyframes clipMe {
	 0%, 100% {
		 clip: rect(0px, 100vw, 10vh, 0px);
	}
	 25% {
		 clip: rect(0px, 2px, 100vh, 0px);
	}
	 50% {
		 clip: rect(90vh, 90vw, 100vh, 0px);
	}
	 75% {
		 clip: rect(0px, 100vw, 100vh, 90vw);
	}
}
 html, body {
	 height: 100%;
}
 body {
	 position: relative;
	 background-color: #0f222b;
}
 *, *::before, *::after {
	 box-sizing: border-box;
}