text: class World {
    constructor(width,height,numberOfBall, radius) {
      //this.pool = pool;
      this.numberOfBall = numberOfBall;
      this.radius = radius;
      this.listBall = [];
      var width = width;
      var height = height;
      for (let i = 0; i < this.numberOfBall; i++) {
        let ball = {
          id: i,
          x:
            Math.floor(Math.random() * (width - 8 * this.radius)) +
            4 * this.radius,
          y:
            Math.floor(Math.random() * (height - 8 * this.radius)) +
            4 * this.radius
        };
        this.listBall.push(ball);
      }
    }
  }
  