#canvas_wrapper{
  border: 1px solid #ccc;
  position: relative;
}

#canvas1{
  position: relative;
  z-index: 0;
}
#canvas2{
  position: absolute;
  top: 0; left: 0;
  z-index: 1;
}
#canvas3{
  position: absolute;
  top: 0; left: 0;
  z-index: 2;
}

#xaxis{
  position: absolute;
  bottom: 5px;
  right: 5px;
  z-index: 5;
}
#yaxis{
  position: absolute;
  top: 5px;
  left: 5px;
  z-index: 5;
}

#main{
  width: 505px;
  margin: 0 auto;
}