function ShowPop(id)
{
   document.getElementById('learn').style.visibility = "hidden";
   document.getElementById('explore').style.visibility = "hidden";
   document.getElementById('enter').style.visibility = "hidden";
   document.getElementById('approach').style.visibility = "hidden";
   document.getElementById('shape').style.visibility = "hidden";
   document.getElementById(id).style.visibility = "visible";
}
function HidePop(id)
{
   document.getElementById(id).style.visibility = "hidden";
}