#canvas{
  width: 80vmin;
  height: 80vmin;
  background-color: #556;
  position: relative;
  margin: 0 auto;
}
#col2{
  left: 27vmin;
  Width: 27vmin;
  height: 80vmin;
  background-color: indianred;
  position: absolute;
  
}
#col3{
  top: 0;
  left: 53vmin;
  Width: 27vmin;
  height: 80vmin;
  background-color: goldenrod;
  position: absolute;
}