public class Square extends Rectangle implements IPricer {
    private double size;

    public Square(double length, double width) throws InstantiationException {
        super(length, width);
        if(length == width){
            this.size = length;
        } else {
            throw new InstantiationException("this is not a square");
        }
    }

    public Square(double size){
        super(size, size);
    }

    @Override
    public String identifySelf() {
        return "I am a Square";
    }

    @Override
    public double getPrice() {
        return size*size*3;
    }
}