.type3 {
    -webkit-mask: url(../images/mask.png) no-repeat center center;
}
.type3:hover{
    -webkit-animation: loop_frames 1s ease-in-out infinite;
     -webkit-animation-direction:alternate;
     -webkit-mask-size: auto 100%;
}
@-webkit-keyframes loop_frames {
     0% { -webkit-mask-size: auto 100%; }
     100% { -webkit-mask-size: auto 70%; }
}

.type4 {
    -webkit-transition: -webkit-mask-position 0.5s ease;
    -webkit-mask-size: 400px 300px;
    -webkit-mask-image: -webkit-gradient(linear, left top, right top, color-stop(0.00, rgba(0,0,0,1)), color-stop(0.90, rgba(0,0,0,1)), color-stop(1.00, rgba(0,0,0,0)));
    -webkit-mask-position-x: 400px;
}
.type4:hover {
     -webkit-mask-position-x: 0;
}