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;
   
    btn2 = createImg('up.png');
    btn2.position(200,200);
    btn2.size(50,50);
    btn2.mouseClicked(vForce)
   
   
     var ball_options = {
      restitution: 0.95,
    }
    
    ground =new Ground(200,390,400,20);
  
  
    ball = Bodies.circle(100,200,20,ball_options);
    World.add(world,ball);
    con =  Matter.Constraint.create({
      pointA : { x : 200,y :20},
      bodyB:ball,
      pointB : {x : 0 , y : 0 },
      length  : 100,
      stiffness : 0.1,
     
    
     })
  
    World.add(world,con)
    
    
  
    rectMode(CENTER);
    ellipseMode(RADIUS);
  }
  
  
  function draw() 
  {
    background(51);
    Engine.update(engine);
    
    
  
    ellipse(ball.position.x,ball.position.y,20);
    fill("white");
    
    
    ground.show();
    line(con.pointA.x,con.pointA.y,ball.position.x,ball.position.y);
  
    Engine.update(engine);
  }
  
  
  function vForce()
  {
    Matter.Body.applyForce(ball,{x:0,y:0},{x:0.05,y:-0});
  }
    
  
  
  