html{width:100%; height:100%;}
body{width:auto; height:100%; display:table;}

#wall{
  position:relative;
  display:table-cell;
  vertical-align:middle;
  width:auto;}

.level{
  position:relative;
  height:350px;}
  
  .level.first{
    display:visible;}

  .level.second{
    display:none;}

  .level.third{
    display:none;}

.picture{
  display:block;
  position:absolute;}

  .picture.p1{top:0px; left:0px;}
  .picture.p2{top:0px; left:700px;}
  .picture.p3{top:0px; left:1150px;}
  .picture.p4{top:0px; left:1600px;}
  .picture.p5{top:0px; left:450px;}
  .picture.p6{top:200px; left:450px;}
  .picture.p7{top:0px; left:550px;}