#slider{
    overflow: hidden;
}
#slider figure{
    position: relative;
    width: 500%;
    margin: 0;
    left: 0;
    animation: 20s slider infinite;
}
#slider figure img {
    width: 20%;
    float: left;
} 
@keyframes slider {
    0%{
        left: 0;
    }
    20%{
        left: 0;
    }
    25%{
        left: -100%;
    }
    45%{
        left: -100%;
    }
    50%{
        left: -200%;
    }
    70%{
        left: -200%;
    }
    75%{
        left: -300%;
    }
    95%{
        left: -300%;
    }
    100%{
        left: -400%;
    }
}