text: const Engine = Matter.Engine;
  const World = Matter.World;
  const Bodies = Matter.Bodies;
  const Body = Matter.Body;
  
  let engine;
  let world;
  var ball;
  var ground;
  var obstacle;
  
  function setup() {
    createCanvas(400, 400);
  
    engine = Engine.create();
    world = engine.world;
  
    var ball_options = {
      restitution: 0.95,
      frictionAir: 0.01
    }
  
    var ground_options = {
      isStatic: true
    };
  
    var obstacle_options = {
      isStatic: true
    };
  
    ground = Bodies.rectangle(200, 390, 400, 20, ground_options);
    World.add(world, ground);
  
    ball = Bodies.circle(100, 10, 20, ball_options);
    World.add(world, ball);
  
    obstacle = Bodies.rectangle(100, 200, 75, 5, obstacle_options);
    World.add(world, obstacle);
  
    rectMode(CENTER);
    ellipseMode(RADIUS);
    noStroke();
  }
  
  
  function draw() {
    background(255);
    Engine.update(engine);
  
    fill(51);
  
    ellipse(ball.position.x, ball.position.y, 20);
  
    push();
    fill(177);
    rect(ground.position.x, ground.position.y, 400, 20);
    pop();
  
    push();
    fill(0, 255, 0);
    rect(obstacle.position.x, obstacle.position.y, 75, 5);
    pop();
  }