private static Shape getRandomShape(){
        Shape randomShape = null;

        switch (getRandomNumber(1, 4)){
            case 1:
                randomShape = new Square(getRandomColor(), getRandomNumber(1, 100));
                break;
            case 2:
                randomShape = new Triangle(getRandomColor(), getRandomNumber(1, 100), getRandomNumber(1, 100));
                break;
            case 3:
                randomShape = new Circle(getRandomColor(), getRandomNumber(1, 100));
                break;
            case 4:
                randomShape = new Trapezium(getRandomColor(), getRandomNumber(1, 100), getRandomNumber(1, 100), getRandomNumber(1, 100), getRandomNumber(1, 100));
                break;
        }
        return randomShape;
    }