private void verifyWithBorder(Integer[] delta) {
    if (this.x < this.minBorder || this.x > this.maxBorder || this.y < this.minBorder || this.y > this.maxBorder) {
      System.out.println("Cannot move when the position is " + this.toString());
      this.x -= delta[0];
      this.y -= delta[1];
    }
  }