animation:myfirst 5s linear 2s infinite alternate;
-moz-animation:myfirst 5s linear 2s infinite alternate;
-webkit-animation:myfirst 5s linear 2s infinite alternate;
-o-animation:myfirst 5s linear 2s infinite alternate;
0% {background:red; left:0px; top:0px;}
25% {background:yellow; left:200px; top:0px;}
50% {background:blue; left:200px; top:200px;}