.box {
width: 50px;
height: 50px;
}
.yellow {
background: yellow;
position: absolute;
top: 50%;
left: 50%;
transform: translate(-50%, -50%);
}
body {
background-color: black;
}
function initialSetup() {
if (document.getElementById("yellow") != null) {
document.getElementById('yellow').style.visibility = 'hidden';
setTimeout("document.getElementById('yellow').style.visibility = 'visible'", 2000);
}