code: function (renderer) {
          var lineWidth = 2;
  
          if (this.isColliding === true) {
              this.color.setColor(255, 0, 0);
          } else {
              this.color.setColor(0, 255, 0);
          }
  
          renderer.setGlobalAlpha(0.5);
          renderer.setColor(this.color);
          renderer.fillRect(0, 0, this.width, this.height);
          renderer.setGlobalAlpha(1.0);
          renderer.setLineWidth(lineWidth);
          renderer.strokeRect(
              lineWidth,
              lineWidth,
              this.width - lineWidth * 2,
              this.height - lineWidth * 2
          );
  
          // reset the colliding flag
          this.isColliding = false;
      }
docs: draw the square