animate.css/source/flippers/flip.css

@keyframes flip {
	0% {
		transform: perspective(400px) translateZ(0) rotateY(0) scale(1);
		animation-timing-function: ease-out;
	}
	40% {
		transform: perspective(400px) translateZ(150px) rotateY(170deg) scale(1);
		animation-timing-function: ease-out;
	}
	50% {
		transform: perspective(400px) translateZ(150px) rotateY(190deg) scale(1);
		animation-timing-function: ease-in;
	}
	80% {
		transform: perspective(400px) translateZ(0) rotateY(360deg) scale(.95);
		animation-timing-function: ease-in;
	}
	100% {
		transform: perspective(400px) translateZ(0) rotateY(360deg) scale(1);
		animation-timing-function: ease-in;
	}
}

.animated.flip {
	backface-visibility: visible;
	animation-name: flip;
}