#container{
    margin: 0 auto;
    width: 500px;
    height: 1000px;
}
div{
    height: 100px;
    width: 250px;
    text-align: center;
    font-size: 100px;
    overflow: hidden;
    position: relative;
}
#DISboven{
    color: turquoise;
    line-height: 200px;
}
#DISonder{
    color: purple;
    line-height: 0px;
}
#CONboven{
    color: purple;
    line-height: 200px;
}
#CONonder{
    color: turquoise;
    line-height: 0px;
}
#NECTboven{
    color: turquoise;
    line-height: 200px;
}
#NECTonder{
    color: purple;
    line-height: 0px;
}
.boven{
    animation: boven 0.1s infinite;
}
.onder{
    animation: onder 0.1s infinite;
}
@keyframes boven{
    0% {left: 0px;}
    50% {left: 5px;}
    100% {left: 0px;}
}
@keyframes onder{
    0% {right: 0px;}
    50% {right: 5px;}
    100%{right: 0px;}
}