text: class Stone{
      constructor(x,y,radius){
          var options = {
              isStatic : false,
              restitution : 0.1,
              friction : 1,
              density : 0.5
          }
          this.body = Bodies.circle(x,y,radius,options);
          this.radius = radius;
          this.image = loadImage("images/stone.png");
          World.add(world,this.body);
      }
      display(){
          push();
          imageMode(CENTER);
          translate(this.body.position.x,this.body.position.y);
          rotate(this.body.angle);
          image(this.image, 0, 0, this.radius*3, this.radius*3);
          pop();
      }
  }