Some simple CSS 

.tile {
  display:  block;
  width:    200px;
  height:   200px;
  position: absolute;
}
#a1 {
  top:  50px;
  left: 50px;
  background-color: #666;
}
#a2 {
  top:  120px;
  left: 120px;
  background-color: #F90;
}