text: const Engine = Matter.Engine;
  const World = Matter.World;
  const Bodies = Matter.Bodies;
  const Body = Matter.Body;
  
  let engine;
  let world;
  
  var tower;
  
  function preload() {
    backgroundImg = loadImage("./assets/background.gif");
    towerImage = loadImage("./assets/tower.png");
  
  }
  
  
  function setup() {
    canvas = createCanvas(1200,600);
  
    engine = Engine.create();
    world = engine.world;
  
  
  
    rectMode(CENTER);
    ellipseMode(RADIUS);
    //Use a new keyword to create a tower object.(challenge 4)
    tower=new Tower(150,350,160,310);
  }
  
  function draw() 
  {
    background(189);
    image(backgroundImg, 0, 0, width, height);
  
    Engine.update(engine);
  //display tower(challenge 4)
  tower.display();
  }
  