.element.now-in-view {
    opacity: 1;
    clip-path: polygon(100% 0, 0 0, 0 100%, 100% 100%);
    -webkit-transition-delay: 250ms;
    -moz-transition-delay: 250ms;
    -ms-transition-delay: 250ms;
    -o-transition-delay: 250ms;
    transition-delay: 250ms;
}

.element {
    position: relative;
    overflow: hidden;
    display: inline-block;
    opacity: 0;
    transition: all 900ms ease;
    -moz-transition: all 900ms ease;
    -webkit-transition: all 900ms ease;
    -ms-transition: all 900ms ease;
    -o-transition: all 900ms ease;
    clip-path: polygon(50% 0, 50% 0, 50% 100%, 50% 100%);
}