div.css3-A{
    -webkit-animation: A 2s ease 0s infinite alternate;
    animation: A 2s ease 0s infinite alternate;
}
@-webkit-keyframes A {
    0%   {-webkit-transform:rotate(0deg);}
    100% {-webkit-transform:rotate(360deg);}
}
@keyframes A {
    0%   {transform:rotate(0deg);}
    100% {transform:rotate(360deg);}
}

CSS3 イージング一覧