anchor.diff:      update_rotation: function()  {
         this.path.rotate(this.rotate_speed);
       },
  +    decrement_scale: function()  {
  +      this.set_scale(this.scaling_rate);
  +    },
  +    increment_scale: function()  {
  +      this.set_scale(20);
  +    },
  +    set_scale: function(amount)  {
  +      this.path.scale(amount);
  +      this.text.characterStyle.fontSize *= amount;
  +    },
       move_to_destination: function()  {
         vector = this.destination - this.path.position;
         this.path.position += vector / 30;
  
positive.code:         }
        }
      },
    });
  
    var Connection = Base.extend({
  
negative.code: 
    function onFrame(event) {
      mover_group.update_positions();
    }
  
    function onMouseDown(event)  {
      mover_group.handle_mouse_down(event);
    }
  </script>
  <canvas id="visualization_canvas" resize>
  