text: 
  const Engine = Matter.Engine;
  const World = Matter.World;
  const Bodies = Matter.Bodies;
  const Body = Matter.Body;
  
  let engine;
  let world;
  
  var ground;
  
  var top_wall;
  var ball;
  
  var btn1;
  var btn2;
  function setup() {
    createCanvas(400,400);
  
    engine = Engine.create();
    world = engine.world;
    
     var ball_options = {
      restitution: 0.95,
    }
     
    
    btn2 = createImg('up.png');
    btn2.position(20,30);
    btn2.size(50,50);
    btn2.mouseClicked(vForce);
    
     
    
    
  
    ground =new Ground(200,390,400,20);
  
  
    ball = Bodies.circle(100,200,20,ball_options);
    World.add(world,ball);
    ball2=Bodies.circle(100,300,20,ball_options);
    ball3=Bodies.circle(100,400,20,ball_options)
    World.add(world,ball2);
    con=Matter.Constraint.create({
      pointA:{x:200,y:20},
      bodyB:ball,
      pointB:{x:0,y:0},
      length:102,
      stiffness:2
    })
  World.add(world,con);
  
  con2=Matter.Constraint.create({
    bodyA:ball,
    pointA:{x:0,y:0},
    bodyB:ball2,
    pointB:{x:0,y:1},
    length:50,
    stiffness:1.3
  })
  
  con3=Matter.Constraint.create({
    bodyA:ball,
    pointA:{x:0,y:1},
    bodyB:ball3,
    pointB:{x:0,y:3},
    length:73,
    stiffness:0.9
  })
  
  World.add(world,con2,con3);
    rectMode(CENTER);
    ellipseMode(RADIUS);
  }
  
  
  function draw() 
  {
    background(51);
    Engine.update(engine);
    line(con.pointA.x,con.pointA.y,ball.position.x,ball.position.y) ;
   line(ball.position.x,ball.position.y,ball2.position.x,ball2.position.y,ball3.position.x,ball3.position.y);
    ellipse(ball.position.x,ball.position.y,20);
    ellipse(ball2.position.x,ball2.position.y,20);
    ellipse(ball3.postion.x,ball3.postion.y,20)
    ground.show();
    strokeWeight(2);
    stroke("black");
    
  }
  
  
  function vForce()
  {
    Matter.Body.applyForce(ball,{x:0,y:0},{x:0.05,y:0});
    
  }