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);
  
  var options={
     pointA:{x:200, y:20},
     bodyB:ball,
     length:150,
     stiffness:1.1,
  
    }
  
    con = Matter.Constraint.create(options);
    World.add(world,con);
    
    
  
    rectMode(CENTER);
    ellipseMode(RADIUS);
  }
  
  
  function draw() 
  {
    background(51);
    Engine.update(engine);
    
    
  
    ellipse(ball.position.x,ball.position.y,20);
    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,y:-0.05});
  }
    
  
  
  