#wrapper {
  margin-left: auto;
    margin-right: auto;
    width: 70%;
}

div {
    -webkit-animation-duration: 1s;
    -webkit-animation-iteration-count: infinite;
    -webkit-animation-timing-function:linear;
    -webkit-backface-visibility: hidden;
    position: absolute;
}

@-webkit-keyframes flip1 {
    from { -webkit-transform: rotateX(0deg); }
    to { -webkit-transform: rotateX(360deg); }
}

div.flip1 {
    -webkit-animation-name: flip1;
}

@-webkit-keyframes flip2 {
    from { -webkit-transform: rotateX(-180deg); }
    to { -webkit-transform: rotateX(180deg); }
}

div.flip2 {
    -webkit-animation-name: flip2;
}